Fix to autogen bits/syscall.h, like i386

libc/sysdeps/linux/powerpc/Makefile

@@ -71,8 +71,9 @@ $(COBJS): %.o : %.c
 	$(STRIPTOOL) -x -R .note -R .comment $*.o
 
 headers:
-	# no arch-specific headers
+	@(TOPDIR=$(TOPDIR) CC=$(CC) /bin/sh $(TOPDIR)/extra/scripts/gen_bits_syscall_h.sh >bits/syscall.h)
 
 clean:
 	rm -f *.[oa] *~ core
+	rm -f bits/syscall.h