[CRIU] [PATCH 1/2] build: only generate soccr config.h if necessary

[Tycho Andersen]

Without this, any rebuild fails with:

make[1]: Entering directory '/home/ubuntu/criu'
make[1]: Entering directory '/home/ubuntu/criu'
  GEN      .gitid
  GEN      criu/include/config.h
  GEN      /home/ubuntu/criu/criu/include/version.h
make[1]: 'compel/plugins/std.built-in.o' is up to date.
make[1]: Leaving directory '/home/ubuntu/criu'
ln: failed to create symbolic link '/home/ubuntu/criu/soccr/config.h': File exists
Makefile:217: recipe for target '/home/ubuntu/criu/soccr/config.h' failed
make: *** [/home/ubuntu/criu/soccr/config.h] Error 1
make: *** Waiting for unfinished jobs....
make[1]: Entering directory '/home/ubuntu/criu'
make[1]: 'compel/compel-host' is up to date.
make[1]: Leaving directory '/home/ubuntu/criu'
make[1]: Leaving directory '/home/ubuntu/criu'

Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
---
 Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 803b3bf..6947d9c 100644
--- a/Makefile
+++ b/Makefile
@@ -214,7 +214,7 @@ include Makefile.compel
 SOCCR_A := soccr/libsoccr.a
 SOCCR_CONFIG := $(SRC_DIR)/soccr/config.h
 $(SOCCR_CONFIG): $(CONFIG_HEADER)
-	$(Q) ln -s ../$(CONFIG_HEADER) $@
+	$(Q) test -f $@ || ln -s ../$(CONFIG_HEADER) $@
 soccr/%: $(SOCCR_CONFIG) .FORCE
 	$(Q) $(MAKE) $(build)=soccr $@
 soccr/built-in.o: $(SOCCR_CONFIG) .FORCE
-- 
2.7.4