[xen staging] build: fix clean targets when subdir-y is used

[patchbot@xxxxxxx]

commit 0c58617f21c9d841190222c54ee7a64845320acd
Author:     Anthony PERARD <anthony.perard@xxxxxxxxxx>
AuthorDate: Tue Sep 7 09:30:25 2021 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Sep 7 09:30:25 2021 +0200

    build: fix clean targets when subdir-y is used
    
    The make variable $(subdir-y) isn't used yet but will be in a
    following patch. Anything in $(subdir-y) doesn't to have a '/' as
    suffix as we already now it's a directory.
    
    Rework the rules so that it doesn't matter whether there is a '/' or
    not. It also mimic more closely to the way Linux's Kbuild descend in
    subdirectories.
    
    FORCE phony target isn't needed anymore running clean, so it can be
    removed.
    
    Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/scripts/Makefile.clean | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/xen/scripts/Makefile.clean b/xen/scripts/Makefile.clean
index 53379e6102..027c200c0e 100644
--- a/xen/scripts/Makefile.clean
+++ b/xen/scripts/Makefile.clean
@@ -12,19 +12,18 @@ include Makefile
 # Figure out what we need to clean from the various variables
 # ==========================================================================
 subdir-all := $(subdir-y) $(subdir-n) $(subdir-) \
-              $(filter %/, $(obj-y) $(obj-n) $(obj-))
+              $(patsubst %/,%, $(filter %/, $(obj-y) $(obj-n) $(obj-)))
 
 DEPS_RM = $(DEPS) $(DEPS_INCLUDE)
 .PHONY: clean
-clean:: $(addprefix _clean_, $(subdir-all))
+clean:: $(subdir-all)
        rm -f *.o .*.o.tmp *~ core $(DEPS_RM)
 
 # Descending
 # ---------------------------------------------------------------------------
 
-_clean_%/: FORCE
-       $(MAKE) $(clean) $*
+PHONY += $(subdir-all)
+$(subdir-all):
+       $(MAKE) $(clean) $@
 
-# Force execution of pattern rules (for which PHONY cannot be directly used).
-.PHONY: FORCE
-FORCE:
+.PHONY: $(PHONY)
--
generated by git-patchbot for /home/xen/git/xen.git#staging