Implement infrastructure around new lexer

The lexer itself is very much incomplete, but this is intended to be a
safe point to revert to should further implementation go south.

Makefile

@@ -56,7 +56,6 @@ rgbasm_obj := \
 	src/asm/asmy.o \
 	src/asm/charmap.o \
 	src/asm/fstack.o \
-	src/asm/globlex.o \
 	src/asm/lexer.o \
 	src/asm/macro.o \
 	src/asm/main.o \
@@ -73,7 +72,7 @@ rgbasm_obj := \
 	src/hashmap.o \
 	src/linkdefs.o
 
-src/asm/globlex.o src/asm/lexer.o src/asm/constexpr.o: src/asm/asmy.h
+src/asm/lexer.o: src/asm/asmy.h
 
 rgblink_obj := \
 	src/link/assign.o \