made geoslib testcode compile again, added the required linker config and a Makefile

testcode/grc/Makefile

@@ -0,0 +1,43 @@
+
+# Just the usual way to find out if we're
+# using cmd.exe to execute make rules.
+ifneq ($(shell echo),)
+  CMD_EXE = 1
+endif
+
+ifdef CMD_EXE
+  NULLDEV = nul:
+  DEL = -del /f
+  RMDIR = rmdir /s /q
+else
+  NULLDEV = /dev/null
+  DEL = $(RM)
+  RMDIR = $(RM) -r
+endif
+
+ifdef CC65_HOME
+  AS = $(CC65_HOME)/bin/ca65
+  CC = $(CC65_HOME)/bin/cc65
+  CL = $(CC65_HOME)/bin/cl65
+  LD = $(CC65_HOME)/bin/ld65
+  GRC = $(CC65_HOME)/bin/grc65
+else
+  AS := $(if $(wildcard ../../../bin/ca65*),../../../bin/ca65,ca65)
+  CC := $(if $(wildcard ../../../bin/cc65*),../../../bin/cc65,cc65)
+  CL := $(if $(wildcard ../../../bin/cl65*),../../../bin/cl65,cl65)
+  LD := $(if $(wildcard ../../../bin/ld65*),../../../bin/ld65,ld65)
+  GRC := $(if $(wildcard ../../../bin/grc65*),../../../bin/grc65,grc65)
+endif
+
+all: test.s vlir.cvt
+
+test.s: test.grc
+	$(GRC) -s test.s test.grc
+
+vlir.cvt: vlir.grc
+	$(GRC) -s vlir.s test.grc
+	$(CL) -t geos -C geos-cbm-overlay.cfg -o vlir.cvt vlir.s vlir0.s vlir1.s vlir2.s
+	
+clean:
+	$(RM) test.s test.h
+	$(RM) vlir.s vlir.cvt