[XEN PATCH v7 29/51] build: add an other explicite rules to not build $(XEN_ROOT)/.config

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

GNU Make will try to rebuild every Makefile included with the
"include" directive, so everytime Config.mk is used, make will try to
build ".config". This would normally not be an issue, unless we happen
to have a rules which match. This is the case with Kconfig in xen/.

While we had a workaround in "xen/Makefile", this ".config" files
becomes an issue again in "xen/tools/kconfig/Makefile". It has a
target "%.config".

Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
 xen/Rules.mk | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/xen/Rules.mk b/xen/Rules.mk
index a62c761be8d1..f1043a78a332 100644
--- a/xen/Rules.mk
+++ b/xen/Rules.mk
@@ -11,6 +11,10 @@ __build:
 -include $(BASEDIR)/include/config/auto.conf
 
 include $(XEN_ROOT)/Config.mk
+
+# Don't try to remake this file included by Config.mk.
+$(XEN_ROOT)/.config: ;
+
 include $(BASEDIR)/scripts/Kbuild.include
 
 ifndef obj
-- 
Anthony PERARD