carefully begin owcc (Watcom C’s POSIX cc wrapper) support

Build.sh

@@ -1,5 +1,5 @@
 #!/bin/sh
-srcversion='$MirOS: src/bin/mksh/Build.sh,v 1.610 2012/12/28 03:35:33 tg Exp $'
+srcversion='$MirOS: src/bin/mksh/Build.sh,v 1.611 2012/12/28 04:58:13 tg Exp $'
 #-
 # Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
 #		2011, 2012
@@ -1025,9 +1025,7 @@ uslc)
 	vv '|' "$CC $CFLAGS $CPPFLAGS $LDFLAGS $NOWARN -V conftest.c $LIBS"
 	;;
 watcom)
-	echo >&2 'Warning: Watcom C Compiler detected. This compiler has not yet
-    been tested for compatibility with mksh. Continue at your
-    own risk, please report success/failure to the developers.'
+	vv '|' "$CC $CFLAGS $CPPFLAGS $LDFLAGS $NOWARN -v conftest.c $LIBS"
 	;;
 xlc)
 	vv '|' "$CC $CFLAGS $CPPFLAGS $LDFLAGS $NOWARN $LIBS -qversion"
@@ -1132,6 +1130,9 @@ elif test $ct = tendra; then
 elif test $ct = ucode; then
 	save_NOWARN=
 	DOWARN=-w2
+elif test $ct = watcom; then
+	save_NOWARN=
+	DOWARN=-Wc,-we
 else
 	test x"$save_NOWARN" = x"" && save_NOWARN=-Wno-error
 	ac_flags 0 wnoerror "$save_NOWARN"
@@ -1528,7 +1529,7 @@ else
 		#define EXTERN
 		#define MKSH_INCLUDES_ONLY
 		#include "sh.h"
-		__RCSID("$MirOS: src/bin/mksh/Build.sh,v 1.610 2012/12/28 03:35:33 tg Exp $");
+		__RCSID("$MirOS: src/bin/mksh/Build.sh,v 1.611 2012/12/28 04:58:13 tg Exp $");
 		int main(void) { printf("Hello, World!\n"); return (0); }
 EOF
 	case $cm in