Remove *.o and *.os running find only once

Makefile

@@ -370,8 +370,7 @@ clean:
 	@if [ -d libc/sysdeps/linux/$(TARGET_ARCH) ]; then		\
 	    $(MAKE) -C libc/sysdeps/linux/$(TARGET_ARCH) clean;		\
 	fi
-	-find . -name \*.o -exec $(RM) {} \;
-	-find . -name \*.os -exec $(RM) {} \;
+	-find . \( -name \*.o -o -name \*.os \) -exec $(RM) {} \;
 
 distclean: clean
 	-find . \( -name core -o -name \*.orig -o -name \*~ -o -name .\#\* \) -exec $(RM) {} \;