fix parallel builds. fixincludes doesn't own that directory, so don't

clean it up.

More recent gcc have a cleaner fix, where fixincludes has been moved to
another directory that it truly owns, but in our case, we do not need to
clean up the fake directory as it's just been created.

okay pascal@, naddy@

lang/gcc/4.2/patches/patch-gcc_Makefile_in

@@ -0,0 +1,14 @@
+$OpenBSD: patch-gcc_Makefile_in,v 1.1 2012/09/23 10:32:16 espie Exp $
+--- gcc/Makefile.in.orig	Tue Apr  1 23:26:19 2008
++++ gcc/Makefile.in	Sat Sep 22 09:42:04 2012
+@@ -3865,8 +3865,8 @@ install-headers: $(INSTALL_HEADERS_DIR)
+ 
+ # Create or recreate the gcc private include file directory.
+ install-include-dir: installdirs
+-	-rm -rf $(DESTDIR)$(libsubdir)/include
+-	mkdir $(DESTDIR)$(libsubdir)/include
++	#-rm -rf $(DESTDIR)$(libsubdir)/include
++	mkdir -p $(DESTDIR)$(libsubdir)/include
+ 	-chmod a+rx $(DESTDIR)$(libsubdir)/include
+ 
+ # Create or recreate the install-tools include file directory.