Removed executable permission on sourced-only files

Bash scripts that are not to be executed standalone should not have
executable permissions.

Author: spog

Makefile

@@ -63,7 +63,7 @@ install:
 	install -d -m 0755 $(INSTALL_LIB)/
 	install -C -m 0755 $(LIB) $(INSTALL_LIB)/
 	install -d -m 0755 $(INSTALL_EXT)/
-	install -C -m 0755 $(EXTS) $(INSTALL_EXT)/
+	install -C -m 0644 $(EXTS) $(INSTALL_EXT)/
 	install -d -m 0755 $(INSTALL_MAN1)/
 	install -C -m 0644 $(MAN1)/$(NAME).1 $(INSTALL_MAN1)/