-// For some reason, this must be defined for common dialogs to work.
-#ifdef __WATCOMC__
-#define INCLUDE_COMMDLG_H 1
-#endif
+// check if to use precompiled headers: do it for most Windows compilers unless
+// explicitly disabled by defining NOPCH
+#if defined(__VISUALC__) || \
+ defined(__DMC__) || \
+ defined(__VISAGECPP__) || \
+ defined(__WATCOMC__) || \
+ defined(__BORLANDC__)