diff --git a/asminc/atari.inc b/asminc/atari.inc
index 29159a177..4992807f8 100644
--- a/asminc/atari.inc
+++ b/asminc/atari.inc
@@ -44,9 +44,34 @@ CLOSE   = $0C           ;close
 STATIS  = $0D           ;status
 SPECIL  = $0E           ;special
 
-; Special Entry Command Equates
+; DOS IOCB command codes
 
-; Screen Commands
+RENAME  = $20           ;rename disk file
+DELETE  = $21           ;delete disk file
+LOCKFL  = $23           ;lock file (set to read-only)
+UNLOCK  = $24           ;unlock file
+POINT   = $25           ;point sector
+NOTE    = $26           ;note sector
+GETFL   = $27           ;get file length
+CHDIR_MYDOS     = $29   ;change directory (MyDOS)
+MKDIR   = $2A           ;make directory (MyDOS/SpartaDOS)
+CHDIR_SPDOS     = $2C   ;change directory (SpartaDOS)
+FORMAT  = $FE           ;format
+
+GETCWD  = $30           ;get current directory (MyDOS/SpartaDOS)
+
+; Special Entry Command Equates
+; DOS Commands
+; Command line table, Index values for (DOSVEC),Y -- COMTAB
+; Compatible with OS/A+, DOS XL and SpartaDOS
+
+COMTAB  = 0             ;DOS entry jump vector
+ZCRNAME = 3             ;file name crunch routine jump vector
+BUFOFF  = 10            ;next parameter buffer offset
+COMFNAM = 33            ;destination buffer for crunch routine
+LBUF    = 63            ;command line input buffer
+
+; Screen IOCB Commands
 
 DRAWLN  = $11           ;draw line
 FILLIN  = $12           ;draw line with right fill
@@ -710,6 +735,9 @@ FPSCR1  = $05EC         ;6-byte floating point temporary
 
 ;LBFEND = $05FF         ;##old## END OF LBUFF
 
+
+DOS     = $0700
+
 ;-------------------------------------------------------------------------
 ; Cartridge Address Equates
 ;-------------------------------------------------------------------------
@@ -1022,29 +1050,6 @@ STOPLN  = $BA           ;2-byte stopped line number
 ERRSAVE = $C3           ;1-byte error code
 PTABW   = $C9           ;1-byte tab width
 
-;-------------------------------------------------------------------------
-; DOS
-;-------------------------------------------------------------------------
-
-DOS     = $0700
-
-RENAME  = $20           ;RENAME DISK FILE
-DELETE  = $21           ;DELETE DISK FILE
-LOCKFL  = $23           ;LOCK FILE TO READ ONLY
-UNLOCK  = $24           ;UNLOCK LOCKED FILE
-POINT   = $25           ;POINT SECTOR
-NOTE    = $26           ;NOTE SECTOR
-FORMAT  = $FE           ;FORMAT
-
-; Command line table, Index values for (DOSVEC),Y -- COMTAB
-; Compatible with OS/A+, DOS XL and SpartaDOS
-
-COMTAB  = 0             ;DOS entry jump vector
-ZCRNAME = 3             ;file name crunch routine jump vector
-BUFOFF  = 10            ;next parameter buffer offset
-COMFNAM = 33            ;destination buffer for crunch routine
-LBUF    = 63            ;command line input buffer
-
 ;-------------------------------------------------------------------------
 ; ATASCII CHARACTER DEFS
 ;-------------------------------------------------------------------------
diff --git a/asminc/stdio.inc b/asminc/stdio.inc
index 835a204b1..18a7541e0 100644
--- a/asminc/stdio.inc
+++ b/asminc/stdio.inc
@@ -41,9 +41,9 @@ _IOLBF          = 1
 _IONBF          = 2
 BUFSIZ          = 256
 EOF             = -1
-.if .defined(__APPLE2__) .or .defined(__APPLE2ENH__)
+.if .defined(__APPLE2__)
 FILENAME_MAX    = 64+1
-.elseif .defined(__ATARI__) .or .defined(__ATARIXL__)
+.elseif .defined(__ATARI__)
 FILENAME_MAX    = 12+1
 .elseif .defined(__LUNIX__)
 FILENAME_MAX    = 80+1
diff --git a/cfg/module.cfg b/cfg/module.cfg
index edc87fb17..349197eb0 100644
--- a/cfg/module.cfg
+++ b/cfg/module.cfg
@@ -10,7 +10,7 @@ SEGMENTS {
     DATA:      load = COMBINED, type = rw,  define = yes;
     BSS:       load = COMBINED, type = bss, define = yes;
     ZEROPAGE:  load = ZP,       type = zp;
-    EXTZP:     load = ZP,       type = zp;
+    EXTZP:     load = ZP,       type = zp,  optional = yes;
 }
 FILES {
     %O: format = o65;
diff --git a/include/apple2.h b/include/apple2.h
index 177159e46..190248b0d 100644
--- a/include/apple2.h
+++ b/include/apple2.h
@@ -37,7 +37,7 @@
 
 
 /* Check for errors */
-#if !defined(__APPLE2__) && !defined(__APPLE2ENH__)
+#if !defined(__APPLE2__)
 #  error This module may only be used when compiling for the Apple ][!
 #endif
 
@@ -142,7 +142,7 @@ extern unsigned char _filetype;  /* Default 6 */
 extern unsigned int  _auxtype;   /* Default 0 */
 
 /* The addresses of the static drivers */
-#ifndef __APPLE2ENH__
+#if !defined(__APPLE2ENH__)
 extern void a2_auxmem_emd[];
 extern void a2_stdjoy_joy[];     /* Referred to by joy_static_stddrv[]   */
 extern void a2_stdmou_mou[];     /* Referred to by mouse_static_stddrv[] */
diff --git a/include/atari.h b/include/atari.h
index ca1f9299c..e47d1ccea 100644
--- a/include/atari.h
+++ b/include/atari.h
@@ -38,7 +38,7 @@
 
 
 /* Check for errors */
-#if !defined(__ATARI__) && !defined(__ATARIXL__)
+#if !defined(__ATARI__)
 #  error This module may only be used when compiling for the Atari!
 #endif
 
diff --git a/include/cbm264.h b/include/cbm264.h
index 9ede10f47..ff7468d30 100644
--- a/include/cbm264.h
+++ b/include/cbm264.h
@@ -39,7 +39,7 @@
 
 
 /* Check for errors */
-#if !defined(__PLUS4__) && !defined(__C16__)
+#if !defined(__C16__)
 #  error This module may only be used when compiling for the Plus/4 or C16!
 #endif
 
diff --git a/include/conio.h b/include/conio.h
index 693e40035..cd6bf3651 100644
--- a/include/conio.h
+++ b/include/conio.h
@@ -59,11 +59,11 @@
 #endif
 
 /* Include the correct machine-specific file */
-#if defined(__APPLE2__)
-#  include <apple2.h>
-#elif defined(__APPLE2ENH__)
+#if defined(__APPLE2ENH__)
 #  include <apple2enh.h>
-#elif defined(__ATARI__) || defined(__ATARIXL__)
+#elif defined(__APPLE2__)
+#  include <apple2.h>
+#elif defined(__ATARI__)
 #  include <atari.h>
 #elif defined(__ATMOS__)
 #  include <atmos.h>
diff --git a/include/dirent.h b/include/dirent.h
index d1d786419..b5e1be135 100644
--- a/include/dirent.h
+++ b/include/dirent.h
@@ -43,7 +43,7 @@
 
 typedef struct DIR DIR;
 
-#if defined(__APPLE2__) || defined(__APPLE2ENH__)
+#if defined(__APPLE2__)
 
 struct dirent {
     char          d_name[16];
@@ -78,7 +78,7 @@ struct dirent {
 #define _DE_ISLBL(t)  (0)
 #define _DE_ISLNK(t)  (0)
 
-#elif defined(__ATARI__) || defined(__ATARIXL__)
+#elif defined(__ATARI__)
 
 struct dirent {
     char          d_name[13];  /* 8.3 + trailing 0 */
diff --git a/include/stdio.h b/include/stdio.h
index b2c4fa67a..c2c735cb0 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -69,9 +69,9 @@ extern FILE* stderr;
 #define TMP_MAX         256
 
 /* Standard defines that are platform dependent */
-#if defined(__APPLE2__) || defined(__APPLE2ENH__)
+#if defined(__APPLE2__)
 #  define FILENAME_MAX  (64+1)
-#elif defined(__ATARI__) || defined(__ATARIXL__)
+#elif defined(__ATARI__)
 #  define FILENAME_MAX  (12+1)
 #elif defined(__LUNIX__)
 #  define FILENAME_MAX  (80+1)
diff --git a/include/time.h b/include/time.h
index 7ac69165b..507d7e29a 100644
--- a/include/time.h
+++ b/include/time.h
@@ -76,7 +76,7 @@ extern struct _timezone {
 
 
 
-#if defined(__ATARI__) || defined(__ATARIXL__)
+#if defined(__ATARI__)
 /* The clock depends on the video standard, so read it at runtime */
 unsigned _clocks_per_sec (void);
 #  define CLK_TCK               _clocks_per_sec()
diff --git a/libsrc/Makefile b/libsrc/Makefile
index 4204f00bb..d855d1580 100644
--- a/libsrc/Makefile
+++ b/libsrc/Makefile
@@ -67,7 +67,8 @@ clean:
 
 else # TARGET
 
-CFLAGS += -Osir -W error
+CA65FLAGS =
+CC65FLAGS = -Osir -W error
 
 EXTZP = cbm510 \
         cbm610 \
@@ -178,7 +179,7 @@ $$($1_OBJS): | $$($1_OBJDIR)
 
 $$($1_DRVPAT): $$($1_OBJPAT) $$(ZPOBJ) | $$($1_DRVDIR)
 	@echo $$(TARGET) - $$(@F)
-	@$$(LD) -o $$@ -t module $$^
+	@$$(LD65) -o $$@ -t module $$^
 
 $$($1_OBJDIR) $$($1_DRVDIR):
 	@$$(call MKDIR,$$@)
@@ -187,8 +188,8 @@ $(TARGET): $$($1_DRVS)
 
 $$($1_STCPAT): $$($1_DRVPAT)
 	@echo $$(TARGET) - $$(<F)
-	@$$(CO) -o $$(@:.o=.s) --code-label _$$(subst -,_,$$(subst .,_,$$(<F))) $$<
-	@$$(CA) -t $$(TARGET) -o $$@ $$(@:.o=.s)
+	@$$(CO65) -o $$(@:.o=.s) --code-label _$$(subst -,_,$$(subst .,_,$$(<F))) $$<
+	@$$(CA65) -t $$(TARGET) -o $$@ $$(@:.o=.s)
 
 OBJS += $$($1_STCS)
 
@@ -200,11 +201,11 @@ endef
 
 $(foreach drvtype,$(DRVTYPES),$(eval $(call DRVTYPE_template,$(drvtype))))
 
-AR := $(if $(wildcard ../bin/ar65*),../bin/ar65,ar65)
-CA := $(if $(wildcard ../bin/ca65*),../bin/ca65,ca65)
-CC := $(if $(wildcard ../bin/cc65*),../bin/cc65,cc65)
-CO := $(if $(wildcard ../bin/co65*),../bin/co65,co65)
-LD := $(if $(wildcard ../bin/ld65*),../bin/ld65,ld65)
+AR65 := $(if $(wildcard ../bin/ar65*),../bin/ar65,ar65)
+CA65 := $(if $(wildcard ../bin/ca65*),../bin/ca65,ca65)
+CC65 := $(if $(wildcard ../bin/cc65*),../bin/cc65,cc65)
+CO65 := $(if $(wildcard ../bin/co65*),../bin/co65,co65)
+LD65 := $(if $(wildcard ../bin/ld65*),../bin/ld65,ld65)
 
 export CC65_HOME := $(abspath ..)
 
@@ -213,7 +214,7 @@ export CC65_HOME := $(abspath ..)
 define ASSEMBLE_recipe
 
 $(if $(TRAVIS),,@echo $(TARGET) - $<)
-@$(CA) -t $(TARGET) $(AFLAGS) --create-dep $(@:.o=.d) -o $@ $<
+@$(CA65) -t $(TARGET) $(CA65FLAGS) --create-dep $(@:.o=.d) -o $@ $<
 
 endef
 
@@ -222,8 +223,8 @@ endef
 define COMPILE_recipe
 
 $(if $(TRAVIS),,@echo $(TARGET) - $<)
-@$(CC) -t $(TARGET) $(CFLAGS) --create-dep $(@:.o=.d) --dep-target $@ -o $(@:.o=.s) $<
-@$(CA) -t $(TARGET) -o $@ $(@:.o=.s)
+@$(CC65) -t $(TARGET) $(CC65FLAGS) --create-dep $(@:.o=.d) --dep-target $@ -o $(@:.o=.s) $<
+@$(CA65) -t $(TARGET) -o $@ $(@:.o=.s)
 
 endef
 
@@ -237,10 +238,10 @@ endef
 
 $(EXTRA_OBJPAT): $(EXTRA_SRCPAT) | ../lib
 	@echo $(TARGET) - $(@F)
-	@$(CA) -t $(TARGET) $(AFLAGS) -o $@ $<
+	@$(CA65) -t $(TARGET) $(CA65FLAGS) -o $@ $<
 
 ../lib/$(TARGET).lib: $(OBJS) | ../lib
-	$(AR) a $@ $?
+	$(AR65) a $@ $?
 
 ../wrk/$(TARGET) ../lib ../targetutil:
 	@$(call MKDIR,$@)
diff --git a/libsrc/apple2/targetutil/Makefile.inc b/libsrc/apple2/targetutil/Makefile.inc
index edc4e852b..7904607b3 100644
--- a/libsrc/apple2/targetutil/Makefile.inc
+++ b/libsrc/apple2/targetutil/Makefile.inc
@@ -4,6 +4,6 @@ DEPS += ../wrk/$(TARGET)/loader.d
 	$(ASSEMBLE_recipe)
 
 ../targetutil/loader.system: ../wrk/$(TARGET)/loader.o $(SRCDIR)/targetutil/loader.cfg | ../targetutil
-	$(LD) -o $@ -C $(filter %.cfg,$^) $(filter-out %.cfg,$^)
+	$(LD65) -o $@ -C $(filter %.cfg,$^) $(filter-out %.cfg,$^)
 
 $(TARGET): ../targetutil/loader.system
diff --git a/libsrc/atari/Makefile.inc b/libsrc/atari/Makefile.inc
index 2658bde1d..d12b54058 100644
--- a/libsrc/atari/Makefile.inc
+++ b/libsrc/atari/Makefile.inc
@@ -13,4 +13,4 @@
 # DYNAMIC_DD     - determine default disk device at runtime (SpartaDOS only)
 #                  needs DEFAULT_DEVICE to be defined, otherwise no effect
 
-AFLAGS += -D NUMDRVS=4 -D LINEBUF=80 -D UCASE_FILENAME=1 -D DEFAULT_DEVICE=1 -D DYNAMIC_DD=1
+CA65FLAGS += -D NUMDRVS=4 -D LINEBUF=80 -D UCASE_FILENAME=1 -D DEFAULT_DEVICE=1 -D DYNAMIC_DD=1
diff --git a/libsrc/atari/clrscr.s b/libsrc/atari/clrscr.s
index 58fb63137..483cd047e 100644
--- a/libsrc/atari/clrscr.s
+++ b/libsrc/atari/clrscr.s
@@ -9,26 +9,26 @@
         .importzp       ptr1
         .import         setcursor
 
+SCRSIZE =       960             ; 40x24: size of default atari screen
+
 _clrscr:lda     SAVMSC          ; screen memory
         sta     ptr1
         lda     SAVMSC+1
         clc
-        adc     #>(40*24)
+        adc     #>(SCRSIZE-1)
         sta     ptr1+1
         lda     #0              ; screen code of space char
         sta     OLDCHR
-        ldy     #<(40*24)       ; 40x24: size of default atari screen
-        ldx     #>(40*24)
+        ldy     #<(SCRSIZE-1)
+        ldx     #>(SCRSIZE-1)
 _clr1:  sta     (ptr1),y
         dey
         bne     _clr1
         sta     (ptr1),y
         dex
         bmi     done
-        ldy     ptr1+1
+        dec     ptr1+1
         dey
-        sty     ptr1+1
-        ldy     #255
         jmp     _clr1
 
 done:   sta     COLCRS
diff --git a/libsrc/atari/fdtable.s b/libsrc/atari/fdtable.s
index 7e3325055..fd9f5021b 100644
--- a/libsrc/atari/fdtable.s
+++ b/libsrc/atari/fdtable.s
@@ -11,7 +11,6 @@
         .import fdt_to_fdi
         .export clriocb
         .export fdtoiocb_down
-        .export findfreeiocb
         .export fddecusage
         .export newfd
 
@@ -87,31 +86,6 @@ loop:   sta     ICHID,x
 .endproc
 
 
-; find a free iocb
-; no entry parameters
-; return ZF = 0/1 for not found/found
-;        index in X if found
-; all registers destroyed
-
-.proc   findfreeiocb
-
-        ldx     #0
-        ldy     #$FF
-loop:   tya
-        cmp     ICHID,x
-        beq     found
-        txa
-        clc
-        adc     #$10
-        tax
-        cmp     #$80
-        bcc     loop
-        inx                     ; return ZF cleared
-found:  rts
-
-.endproc        ; findfreeiocb
-
-
 ; decrements usage counter for fd
 ; if 0 reached, it's marked as unused
 ; get fd index in tmp2
diff --git a/libsrc/atari/findfreeiocb.inc b/libsrc/atari/findfreeiocb.inc
new file mode 100644
index 000000000..92140efd4
--- /dev/null
+++ b/libsrc/atari/findfreeiocb.inc
@@ -0,0 +1,23 @@
+; find a free iocb
+; no entry parameters
+; return ZF = 0/1 for not found/found
+;        index in X if found
+; all registers destroyed
+
+.proc   findfreeiocb
+
+        ldx     #0
+        ldy     #$FF
+loop:   tya
+        cmp     ICHID,x
+        beq     found
+        txa
+        clc
+        adc     #$10
+        tax
+        cmp     #$80
+        bcc     loop
+        inx                     ; return ZF cleared
+found:  rts
+
+.endproc        ; findfreeiocb
diff --git a/libsrc/atari/findfreeiocb.s b/libsrc/atari/findfreeiocb.s
new file mode 100644
index 000000000..a500b1f77
--- /dev/null
+++ b/libsrc/atari/findfreeiocb.s
@@ -0,0 +1,7 @@
+;
+; Christian Groessler, June-2013
+;
+
+        .include "atari.inc"
+        .export findfreeiocb
+        .include "findfreeiocb.inc"
diff --git a/libsrc/atari/initcwd.s b/libsrc/atari/initcwd.s
index 19df6a5a4..d7b574314 100644
--- a/libsrc/atari/initcwd.s
+++ b/libsrc/atari/initcwd.s
@@ -11,7 +11,7 @@
 
         jsr     findfreeiocb
         bne     oserr
-        lda     #48
+        lda     #GETCWD
         sta     ICCOM,x
         lda     #<__cwd
         sta     ICBLL,x
diff --git a/libsrc/atari/lseek.s b/libsrc/atari/lseek.s
index bf934294c..889976f5b 100644
--- a/libsrc/atari/lseek.s
+++ b/libsrc/atari/lseek.s
@@ -68,7 +68,7 @@ iocberr:jsr     incsp6
 
 ; SEEK_CUR
 cur:    ldx     tmp3
-        lda     #38             ; NOTE
+        lda     #NOTE
         sta     ICCOM,x
         jsr     CIOV            ; read it
         bmi     xxerr
@@ -84,7 +84,7 @@ l01:    lda     ICAX3,x         ; low byte of position
 
 ; SEEK_END
 end:    ldx     tmp3
-        lda     #39             ; get file size
+        lda     #GETFL
         sta     ICCOM,x
         jsr     CIOV
         bpl     l01
@@ -126,7 +126,7 @@ ret:    jsr     incsp6
 .if 0
         ; return exactly the position DOS has
         ldx     tmp3
-        lda     #38             ; NOTE
+        lda     #NOTE
         sta     ICCOM,x
         jsr     CIOV            ; read it
         bmi     xxerr
@@ -168,7 +168,7 @@ seek:   jsr     ldax0sp         ; get lower word of new offset
         sta     ICAX4,x
         lda     ptr4
         sta     ICAX5,x
-        lda     #37             ;POINT
+        lda     #POINT
         sta     ICCOM,x
         jsr     CIOV
         bpl     ret
@@ -201,7 +201,7 @@ chk_supp:
         cmp     #$40
         bcs     supp1           ; SD-X (ver 4.xx) supports seeking on all disks
         ldx     tmp3            ; iocb to use
-        lda     #39             ; get file size
+        lda     #GETFL
         sta     ICCOM,x
         jsr     CIOV
         bmi     notsupp         ; error code ? should be 168 (invalid command)
diff --git a/libsrc/atari/syschdir.s b/libsrc/atari/syschdir.s
index 9fc45edbd..16cb3a1fe 100644
--- a/libsrc/atari/syschdir.s
+++ b/libsrc/atari/syschdir.s
@@ -58,9 +58,9 @@ ucok1:
         lda     __dos_type
         cmp     #SPARTADOS
         beq     :+
-        lda     #41
+        lda     #CHDIR_MYDOS
         .byte   $2C             ; BIT <abs>
-:       lda     #44
+:       lda     #CHDIR_SPDOS
         sta     ICCOM,x
         lda     #0
         sta     ICAX1,x
diff --git a/libsrc/atari/sysmkdir.s b/libsrc/atari/sysmkdir.s
index de3252ced..56a068757 100644
--- a/libsrc/atari/sysmkdir.s
+++ b/libsrc/atari/sysmkdir.s
@@ -61,7 +61,7 @@ ucok1:
         sta     ICBAH,y
         tya
         tax
-        lda     #42
+        lda     #MKDIR
         sta     ICCOM,x
         lda     #8
         sta     ICAX1,x
diff --git a/libsrc/dbg/dbg.c b/libsrc/dbg/dbg.c
index 68453be6f..00ff28722 100644
--- a/libsrc/dbg/dbg.c
+++ b/libsrc/dbg/dbg.c
@@ -47,7 +47,7 @@ static char GetKeyUpdate (void);
 
 
 /* Color definitions */
-#if defined(__PLUS4__) || defined(__C16__)
+#if defined(__C16__)
 #  define COLOR_BORDER          (BCOLOR_DARKBLUE | CATTR_LUMA6)
 #  define COLOR_BACKGROUND      COLOR_WHITE
 #  define COLOR_TEXTHIGH        COLOR_BLACK
@@ -63,7 +63,7 @@ static char GetKeyUpdate (void);
 #    define COLOR_FRAMEHIGH     COLOR_WHITE
 #    define COLOR_FRAMELOW      COLOR_GRAY3
 #  else
-#    if defined(__APPLE2__) || defined(__APPLE2ENH__)
+#    if defined(__APPLE2__)
 #      define COLOR_BORDER      COLOR_BLACK
 #      define COLOR_BACKGROUND  COLOR_BLACK
 #      define COLOR_TEXTHIGH    COLOR_BLACK
@@ -93,7 +93,7 @@ static char GetKeyUpdate (void);
 #  define MAX_X         80
 #  define MAX_Y         25
 #  define DUMP_BYTES    16
-#elif defined(__APPLE2__) || defined(__APPLE2ENH__) || defined(__ATARI__) || defined(__ATARIXL__)
+#elif defined(__APPLE2__) || defined(__ATARI__)
 #  define MAX_X         40
 #  define MAX_Y         24
 #  define DUMP_BYTES     8
@@ -104,7 +104,7 @@ static char GetKeyUpdate (void);
 #endif
 
 /* Replacement key definitions */
-#if defined(__APPLE2__) || defined(__LYNX__) || defined(__SIM6502__) || defined (__SIM65C02__) || defined(__SUPERVISION__)
+#ifndef CH_DEL
 #  define CH_DEL        ('H' - 'A' + 1)         /* Ctrl+H */
 #endif
 
diff --git a/libsrc/geos-apple/Makefile.inc b/libsrc/geos-apple/Makefile.inc
index 1adc1b5a4..366d35899 100644
--- a/libsrc/geos-apple/Makefile.inc
+++ b/libsrc/geos-apple/Makefile.inc
@@ -1 +1 @@
-AFLAGS += -I geos-apple -I geos-common
+CA65FLAGS += -I geos-apple -I geos-common
diff --git a/libsrc/geos-apple/targetutil/Makefile.inc b/libsrc/geos-apple/targetutil/Makefile.inc
index b5b2d3671..01ae3f55c 100644
--- a/libsrc/geos-apple/targetutil/Makefile.inc
+++ b/libsrc/geos-apple/targetutil/Makefile.inc
@@ -9,6 +9,6 @@ DEPS += ../wrk/$(TARGET)/convert.d
 	@$(MAKE) --no-print-directory apple2enh
 
 ../targetutil/convert.system: ../wrk/$(TARGET)/convert.o ../lib/apple2enh.lib | ../targetutil
-	$(LD) -o $@ -C apple2enh-system.cfg $^
+	$(LD65) -o $@ -C apple2enh-system.cfg $^
 
 $(TARGET): ../targetutil/convert.system
diff --git a/libsrc/geos-cbm/Makefile.inc b/libsrc/geos-cbm/Makefile.inc
index 9bf34d3fd..423ad8b54 100644
--- a/libsrc/geos-cbm/Makefile.inc
+++ b/libsrc/geos-cbm/Makefile.inc
@@ -1 +1 @@
-AFLAGS += -I geos-cbm -I geos-common
+CA65FLAGS += -I geos-cbm -I geos-common
diff --git a/libsrc/runtime/zeropage.s b/libsrc/runtime/zeropage.s
index b4af44e33..2bbe7ceee 100644
--- a/libsrc/runtime/zeropage.s
+++ b/libsrc/runtime/zeropage.s
@@ -22,10 +22,3 @@ tmp2:           .res    1
 tmp3:           .res    1
 tmp4:           .res    1
 regbank:        .res    regbanksize     ; Register bank
-
-; Add an empty EXTZP zeropage segment to avoid linker warnings that this
-; segment does not exist (it does not exist in most builtin linker configs
-; but is used when linking modules).
-
-.segment        "EXTZP" : zeropage
-
diff --git a/libsrc/sim6502/exehdr.s b/libsrc/sim6502/exehdr.s
index 9c895834c..865bd6553 100644
--- a/libsrc/sim6502/exehdr.s
+++ b/libsrc/sim6502/exehdr.s
@@ -6,8 +6,6 @@
 
         .export         __EXEHDR__ : absolute = 1       ; Linker referenced
 
-; ------------------------------------------------------------------------
-
         .segment        "EXEHDR"
 
         .byte   .defined(__SIM65C02__)
diff --git a/samples/mandelbrot.c b/samples/mandelbrot.c
index 6c58cea97..0ba4ebd2c 100644
--- a/samples/mandelbrot.c
+++ b/samples/mandelbrot.c
@@ -28,7 +28,7 @@
 #define divfp(_a,_b)    ((((signed long)_a)<<fpshift)/(_b))
 
 /* Workaround missing clock stuff */
-#if defined(__APPLE2__) || defined(__APPLE2ENH__)
+#ifdef __APPLE2__
 #  define clock()       0
 #  define CLK_TCK       1
 #endif
diff --git a/samples/multidemo.c b/samples/multidemo.c
index 6585b2057..367ce39e1 100644
--- a/samples/multidemo.c
+++ b/samples/multidemo.c
@@ -57,7 +57,7 @@ void log (char *msg)
 
 
 /* In a real-world overlay program one would probably not use a #pragma but
- * rather place the all the code of certain source files into the overlay by
+ * rather place all the code of certain source files into the overlay by
  * compiling them with --code-name OVERLAY1.
  */
 #pragma code-name (push, "OVERLAY1");
diff --git a/samples/overlaydemo.c b/samples/overlaydemo.c
index 8e67d771c..a3fb132e1 100644
--- a/samples/overlaydemo.c
+++ b/samples/overlaydemo.c
@@ -33,7 +33,7 @@ void log (char *msg)
 
 
 /* In a real-world overlay program one would probably not use a #pragma but
- * rather place the all the code of certain source files into the overlay by
+ * rather place all the code of certain source files into the overlay by
  * compiling them with --code-name OVERLAY1.
  */
 #pragma code-name (push, "OVERLAY1");
diff --git a/samples/sieve.c b/samples/sieve.c
index 9ecbab020..9d166b768 100644
--- a/samples/sieve.c
+++ b/samples/sieve.c
@@ -12,7 +12,7 @@
 
 
 /* Workaround missing clock stuff */
-#if defined(__APPLE2__) || defined(__APPLE2ENH__)
+#ifdef __APPLE2__
 #  define clock()               0
 #  define CLOCKS_PER_SEC        1
 #endif
diff --git a/src/Makefile b/src/Makefile
index 8c4c6861e..3d0463147 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -12,11 +12,19 @@ PROGS = ar65  \
         sim65 \
         sp65
 
-CA65_INC := $(abspath ../asminc)
-CC65_INC := $(abspath ../include)
-LD65_LIB := $(abspath ../lib)
-LD65_OBJ := $(abspath ../lib)
-LD65_CFG := $(abspath ../cfg)
+ifdef prefix
+  CA65_INC = $(prefix)/lib/cc65/asminc
+  CC65_INC = $(prefix)/lib/cc65/include
+  LD65_LIB = $(prefix)/lib/cc65/lib
+  LD65_OBJ = $(prefix)/lib/cc65/lib
+  LD65_CFG = $(prefix)/lib/cc65/cfg
+else
+  CA65_INC := $(abspath ../asminc)
+  CC65_INC := $(abspath ../include)
+  LD65_LIB := $(abspath ../lib)
+  LD65_OBJ := $(abspath ../lib)
+  LD65_CFG := $(abspath ../cfg)
+endif
 
 CFLAGS += -MMD -MP -O -std=c89 -I common \
           -Wall -Wextra -Wno-char-subscripts -Werror \
diff --git a/src/ca65/main.c b/src/ca65/main.c
index 1f98e46ae..4b2f9d178 100644
--- a/src/ca65/main.c
+++ b/src/ca65/main.c
@@ -209,6 +209,7 @@ static void SetSys (const char* Sys)
             break;
 
         case TGT_ATARIXL:
+            NewSymbol ("__ATARI__", 1);
             NewSymbol ("__ATARIXL__", 1);
             break;
 
@@ -229,7 +230,8 @@ static void SetSys (const char* Sys)
             break;
 
         case TGT_PLUS4:
-            CBMSystem ("__PLUS4__");
+            CBMSystem ("__C16__");
+            NewSymbol ("__PLUS4__", 1);
             break;
 
         case TGT_CBM510:
@@ -253,6 +255,7 @@ static void SetSys (const char* Sys)
             break;
 
         case TGT_APPLE2ENH:
+            NewSymbol ("__APPLE2__", 1);
             NewSymbol ("__APPLE2ENH__", 1);
             break;
 
diff --git a/src/cc65/codeent.c b/src/cc65/codeent.c
index 7372af338..21eef8fe5 100644
--- a/src/cc65/codeent.c
+++ b/src/cc65/codeent.c
@@ -412,7 +412,7 @@ int CE_IsKnownImm (const CodeEntry* E, unsigned long Num)
 
 
 
-int CE_UseLoadFlags (const CodeEntry* E)
+int CE_UseLoadFlags (CodeEntry* E)
 /* Return true if the instruction uses any flags that are set by a load of
  * a register (N and Z).
  */
@@ -427,7 +427,7 @@ int CE_UseLoadFlags (const CodeEntry* E)
         while (E->Info & OF_UBRA) {
 
             /* Remember the entry so we can detect loops */
-            CollAppend (&C, (void*) E);
+            CollAppend (&C, E);
 
             /* Check the target */
             if (E->JumpTo == 0 || CollIndex (&C, E->JumpTo->Owner) >= 0) {
diff --git a/src/cc65/codeent.h b/src/cc65/codeent.h
index 634034c6b..72ce626bb 100644
--- a/src/cc65/codeent.h
+++ b/src/cc65/codeent.h
@@ -219,7 +219,7 @@ INLINE int CE_IsCallTo (const CodeEntry* E, const char* Name)
 #  define CE_IsCallTo(E, Name) ((E)->OPC == OP65_JSR && strcmp ((E)->Arg, (Name)) == 0)
 #endif
 
-int CE_UseLoadFlags (const CodeEntry* E);
+int CE_UseLoadFlags (CodeEntry* E);
 /* Return true if the instruction uses any flags that are set by a load of
  * a register (N and Z).
  */
diff --git a/src/cc65/main.c b/src/cc65/main.c
index 6d9472143..a27822ed8 100644
--- a/src/cc65/main.c
+++ b/src/cc65/main.c
@@ -165,6 +165,7 @@ static void SetSys (const char* Sys)
             break;
 
         case TGT_ATARIXL:
+            DefineNumericMacro ("__ATARI__", 1);
             DefineNumericMacro ("__ATARIXL__", 1);
             break;
 
@@ -185,7 +186,8 @@ static void SetSys (const char* Sys)
             break;
 
         case TGT_PLUS4:
-            cbmsys ("__PLUS4__");
+            cbmsys ("__C16__");
+            DefineNumericMacro ("__PLUS4__", 1);
             break;
 
         case TGT_CBM510:
@@ -209,6 +211,7 @@ static void SetSys (const char* Sys)
             break;
 
         case TGT_APPLE2ENH:
+            DefineNumericMacro ("__APPLE2__", 1);
             DefineNumericMacro ("__APPLE2ENH__", 1);
             break;
 
diff --git a/testcode/lib/em-test.c b/testcode/lib/em-test.c
index a6feed938..c7fee6a59 100644
--- a/testcode/lib/em-test.c
+++ b/testcode/lib/em-test.c
@@ -16,10 +16,10 @@
 #define DRIVERNAME      "cbm510-ram.emd"
 #elif defined(__CBM610__)
 #define DRIVERNAME      "cbm610-ram.emd"
-#elif defined(__APPLE2__)
-#define DRIVERNAME      "a2.auxmem.emd"
 #elif defined(__APPLE2ENH__)
 #define DRIVERNAME      "a2e.auxmem.emd"
+#elif defined(__APPLE2__)
+#define DRIVERNAME      "a2.auxmem.emd"
 #else
 #define DRIVERNAME      "unknown"
 #error "Unknown target system"
diff --git a/testcode/lib/ft.c b/testcode/lib/ft.c
index 586bace45..ff335240d 100644
--- a/testcode/lib/ft.c
+++ b/testcode/lib/ft.c
@@ -25,7 +25,7 @@
 extern int getsp(void);  /* is provided in getsp.s */
 
 /* Atari's fd indirection table */
-#if defined(__ATARI__) || defined(__ATARIXL__)
+#ifdef __ATARI__
 extern char __fd_index[];
 struct fd_t {
   char usage;
@@ -74,7 +74,7 @@ int main(int argc,char **argv)
         return(0);
     }
     printf("open success -- handle = $%x, sp = %d\n",fd,csp);
-#if defined(__ATARI__) || defined(__ATARIXL__)
+#ifdef __ATARI__
     printf("fd_index:\n ");
     for (i=0; i<12; i++) printf("%02X ",__fd_index[i]);
     printf("\nfd_table:\n");
diff --git a/testcode/lib/mul-test.c b/testcode/lib/mul-test.c
index 5df713072..5db42d4ab 100644
--- a/testcode/lib/mul-test.c
+++ b/testcode/lib/mul-test.c
@@ -18,7 +18,7 @@ static const unsigned char small_bar[8] = {
     ' ', 0xa5, 0xb4, 0xb5, 0xa1, 0xb6, 0xaa, 0xa7
 };
 
-#elif defined(__ATARI__) || defined(__ATARIXL__)
+#elif defined(__ATARI__)
 #endif
 
 /* Screen co-ordinates for the progress meter */
@@ -39,7 +39,7 @@ static void ProgressMeter (unsigned Val)
     revers (revers_bar[Val]);
     cputc (small_bar[Val]);
 
-#elif defined(__ATARI__) || defined(__ATARIXL__)
+#elif defined(__ATARI__)
 #endif
 
     revers (0);
diff --git a/testcode/lib/ser-test.c b/testcode/lib/ser-test.c
index a3f92b633..c929189a3 100644
--- a/testcode/lib/ser-test.c
+++ b/testcode/lib/ser-test.c
@@ -13,10 +13,10 @@
 #define DRIVERNAME      "plus4-stdser.ser"
 #elif defined(__CBM610__)
 #define DRIVERNAME      "cbm610-std.ser"
-#elif defined(__APPLE2__)
-#define DRIVERNAME      "a2.ssc.ser"
 #elif defined(__APPLE2ENH__)
 #define DRIVERNAME      "a2e.ssc.ser"
+#elif defined(__APPLE2__)
+#define DRIVERNAME      "a2.ssc.ser"
 #else
 #define DRIVERNAME      "unknown"
 #error "Unknown target system"