feat: add M2 type checking and C emission

fec/build-dos.bat

@@ -11,12 +11,37 @@ if exist diag.obj del diag.obj
 if exist lexer.obj del lexer.obj
 if exist ast.obj del ast.obj
 if exist parser.obj del parser.obj
+if exist types.obj del types.obj
+if exist check.obj del check.obj
+if exist emitc.obj del emitc.obj
+if exist emit_c.obj del emit_c.obj
 if exist driver.obj del driver.obj
 
 if "%WATCOM%"=="" set WATCOM=C:\DEVEL\WATCOMC
 if not exist %WATCOM%\BINW\WCL.EXE goto build_fail
 set PATH=%WATCOM%\BINW;%WATCOM%\BINP;%PATH%
-wcl -q -za -wx -bt=dos -k32768 -fe=fec.exe src\arena.c src\diag.c src\lexer.c src\ast.c src\parser.c src\driver.c
+wcl -q -za -wx -bt=dos -ml -k32768 -c -fo=arena.obj src\arena.c
+if errorlevel 1 goto build_fail
+wcl -q -za -wx -bt=dos -ml -k32768 -c -fo=diag.obj src\diag.c
+if errorlevel 1 goto build_fail
+wcl -q -za -wx -bt=dos -ml -k32768 -c -fo=lexer.obj src\lexer.c
+if errorlevel 1 goto build_fail
+wcl -q -za -wx -bt=dos -ml -k32768 -c -fo=ast.obj src\ast.c
+if errorlevel 1 goto build_fail
+wcl -q -za -wx -bt=dos -ml -k32768 -c -fo=parser.obj src\parser.c
+if errorlevel 1 goto build_fail
+wcl -q -za -wx -bt=dos -ml -k32768 -c -fo=types.obj src\types.c
+if errorlevel 1 goto build_fail
+wcl -q -za -wx -bt=dos -ml -k32768 -c -fo=check.obj src\check.c
+if errorlevel 1 goto build_fail
+rem Use an unambiguous short object name for the emit_c source.
+wcl -q -za -wx -bt=dos -ml -k32768 -c -fo=emitc.obj src\emit_c.c
+if errorlevel 1 goto build_fail
+wcl -q -za -wx -bt=dos -ml -k32768 -c -fo=driver.obj src\driver.c
+if errorlevel 1 goto build_fail
+rem DOS command lines are limited to roughly 126 characters. All stale objects
+rem were removed above, so the wildcard contains exactly this build's objects.
+wcl -q -za -wx -bt=dos -ml -k32768 -fe=fec.exe *.obj
 if errorlevel 1 goto build_fail
 if not exist fec.exe goto build_fail
 echo OK>BUILD.OK