Include `sys/types.h` header to get `mode_t`
Do not depend on it being included by other system headers.
It is not included by others on musl-libc, for example.
diff --git a/Source/cmStandardIncludes.h b/Source/cmStandardIncludes.h
index 468a589..e212616 100644
--- a/Source/cmStandardIncludes.h
+++ b/Source/cmStandardIncludes.h
@@ -54,6 +54,8 @@
#if defined( _MSC_VER )
typedef unsigned short mode_t;
+#else
+# include <sys/types.h>
#endif
// use this class to shrink the size of symbols in .o files
