Data files should not be executable

By default, the install command sets permissions on files that
it copies so that they are executable; this does not make sense
for data files.  Modify to install commands for data files so
that they are not executable.

Signed-off-by: Dan Cross <crossd@gmail.com>

src/GNUMakefile.common

@@ -117,9 +117,9 @@ install:		all
 			$(MKDIR) -p $(LIBDIR)/UI
 			$(MKDIR) -p $(LIBDIR)/UI/bitmaps
 			$(MKDIR) -p $(LIBDIR)/UI/help
-			$(INSTALL) $(SUBDIR_UI)/*.tk $(SUBDIR_UI)/*.ad $(LIBDIR)/UI
-			$(INSTALL) $(SUBDIR_UI)/bitmaps/* $(LIBDIR)/UI/bitmaps
-			$(INSTALL) $(SUBDIR_UI)/help/* $(LIBDIR)/UI/help
+			$(INSTALL) -m 644 $(SUBDIR_UI)/*.tk $(SUBDIR_UI)/*.ad $(LIBDIR)/UI
+			$(INSTALL) -m 644 $(SUBDIR_UI)/bitmaps/* $(LIBDIR)/UI/bitmaps
+			$(INSTALL) -m 644 $(SUBDIR_UI)/help/* $(LIBDIR)/UI/help
 			$(INSTALL) $(BIN_BSVC) $(BINDIR)
 
 clean: