Apple2: Make 80-columns support dynamic on apple2 target

Add a machinetype identifier to help us quickly identify
Apple //e (bit 7) and //e enhanced (bit 6).

Use it in conio functions for 80-columns code instead of
relying entirely on the __APPLE2ENH__ target.

Move videomode() to the apple2 target, and have it return
an error if 80-columns hardware is not available - this
is a lie for now, it is considered available on //e enhanced,
which may not be true, and not available on //e, which
may also be not true. An ulterior patch will make that
check correctly.

Adapt the box/line drawing characters so that one can use
MouseText on the apple2 target if it is available, by
defining DYN_DRAW_BOX. No change by default: MouseText is
considered available on apple2enh and not available on
apple2.

libsrc/apple2/cputc.s

@@ -5,13 +5,13 @@
 ; void __fastcall__ cputc (char c);
 ;
 
-        .ifdef  __APPLE2ENH__
         .constructor    initconio
-        .endif
         .export         _cputcxy, _cputc
         .export         cputdirect, newline, putchar, putchardirect
         .import         gotoxy, VTABZ
+
         .ifndef __APPLE2ENH__
+        .import         machinetype
         .import         uppercasemask
         .endif
 
@@ -22,12 +22,16 @@
 
         .segment        "ONCE"
 
-        .ifdef  __APPLE2ENH__
 initconio:
+        .ifndef __APPLE2ENH__
+        bit     machinetype
+        bmi     :+
+        rts
+:
+        .endif
         sta     SETALTCHAR      ; Switch in alternate charset
         bit     LORES           ; Limit SET80COL-HISCR to text
         rts
-        .endif
 
         .code
 
@@ -52,14 +56,22 @@ _cputc:
 
 cputdirect:
         jsr     putchar
-        .ifdef  __APPLE2ENH__
+
+        .ifndef __APPLE2ENH__
+        bit     machinetype
+        bpl     :+
+        .endif
         bit     RD80VID         ; In 80 column mode?
         bpl     :+
         inc     OURCH           ; Bump to next column
         lda     OURCH
+        .ifdef __APPLE2ENH__
         bra     check           ; Must leave CH alone
-:       .endif
-        inc     CH              ; Bump to next column
+        .else
+        jmp     check
+        .endif
+
+:       inc     CH              ; Bump to next column
         lda     CH
 check:  cmp     WNDWDTH
         bcc     done
@@ -67,13 +79,24 @@ check:  cmp     WNDWDTH
 left:
         .ifdef  __APPLE2ENH__
         stz     CH              ; Goto left edge of screen
-        bit     RD80VID         ; In 80 column mode?
-        bpl     done
-        stz     OURCH           ; Goto left edge of screen
         .else
-        lda     #$00            ; Goto left edge of screen
+        lda     #$00
         sta     CH
         .endif
+
+        .ifndef __APPLE2ENH__
+        bit     machinetype
+        bpl     done
+        .endif
+
+        bit     RD80VID         ; In 80 column mode?
+        bpl     done
+        .ifdef  __APPLE2ENH__
+        stz     OURCH           ; Goto left edge of screen
+        .else
+        sta     OURCH
+        .endif
+
 done:   rts
 
 newline:
@@ -100,8 +123,14 @@ mask:   and     INVFLG          ; Apply normal, inverse, flash
 putchardirect:
         tax
         ldy     CH
-        .ifdef  __APPLE2ENH__
+
         sec                     ; Assume main memory
+
+        .ifndef __APPLE2ENH__
+        bit     machinetype
+        bpl     put
+        .endif
+
         bit     RD80VID         ; In 80 column mode?
         bpl     put             ; No, just go ahead
         lda     OURCH
@@ -111,14 +140,13 @@ putchardirect:
         php
         sei                     ; No valid MSLOT et al. in aux memory
         bit     HISCR           ; Assume SET80COL
-        .endif
+
 put:    lda     (BASL),Y        ; Get current character
         sta     tmp3            ; Save old character for _cgetc
         txa
         sta     (BASL),Y
-        .ifdef  __APPLE2ENH__
+
         bcs     :+              ; In main memory
         bit     LOWSCR
         plp
-:       .endif
-        rts
+:       rts