From: Juergen Gross <jgross@suse.com>
Date: Tue, 13 Dec 2016 15:38:06 +0000 (+0100)
Subject: stubdom: modify ioemu linkfarm only if necessary
X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~3147
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=0738d6fe7116cc2398bcb557c957ab38b712fe96;p=xen.git

stubdom: modify ioemu linkfarm only if necessary

Several stubdom libraries are being rebuilt each time a top level make
is called as they depend on stubdom/ioemu/linkfarm.stamp which is
depending on tools/qemu-xen-traditional-dir. Unfortunately this
directory is modified by each "make tools" call.

This can be avoided by writing stubdom/ioemu/linkfarm.stamp only if
a source file beneath tools/qemu-xen-traditional-dir has been added
or removed.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
---

diff --git a/stubdom/Makefile b/stubdom/Makefile
index bc49cfe48f..f85821088d 100644
--- a/stubdom/Makefile
+++ b/stubdom/Makefile
@@ -298,9 +298,13 @@ ioemu/linkfarm.stamp: $(XEN_ROOT)/tools/qemu-xen-traditional-dir
 	(cd $$src && find *	! -type l  -type f  $(addprefix ! -name ,	\
 			'*.[oda1]' 'config-*' config.mak qemu-dm qemu-img-xen	\
 			'*.html' '*.pod'					\
-			)) |							\
-	    while read f; do rm -f "$$f"; ln -s "$$src/$$f" "$$f"; done
-	touch ioemu/linkfarm.stamp
+			)) >linkfarm.stamp.tmp;				\
+	cmp -s linkfarm.stamp.tmp linkfarm.stamp &&			\
+		rm linkfarm.stamp.tmp || {				\
+		mv linkfarm.stamp.tmp linkfarm.stamp;			\
+		cat linkfarm.stamp | while read f;			\
+			do rm -f "$$f"; ln -s "$$src/$$f" "$$f"; done;	\
+	}
 else
 export QEMU_ROOT