configure chmod 755 etc.

lib/tcov.c:
- can't be cross-compiled (needs stdio.h)
- can be included in libtcc1.a

Reason why bt-xxx.o/bcheck.o are linked separatly is because we
don't want then to linked into exe's and dlls at the same time.

c67-gen.c

@@ -108,6 +108,8 @@ enum {
 /* maximum alignment (for aligned attribute support) */
 #define MAX_ALIGN     8
 
+#undef CONFIG_TCC_BCHECK
+
 /******************************************************/
 #else /* ! TARGET_DEFS_ONLY */
 /******************************************************/