[PATCH] tools/build: make in-target rule robust against too long argument error

[<changqing.li@windriver.com>]

From: Changqing Li <changqing.li@windriver.com>

The command length of in-target scales with the depth of the directory
times the number of objects in the Makefile. When there are many
objects, and O=[absolute_path] is set, and the absolute_path is
relatively long. It is possile that this line "$(call
if_changed,$(host)ld_multi)" will report error:
"make[4]: /bin/sh: Argument list too long"

For example, build perf tools with O=/long/output/path

Like built-in.a and *.mod rules in scripts/Makefile.build, add
$(objpredix)/ by the shell command instead of by Make's builtin
function.

Signed-off-by: Changqing Li <changqing.li@windriver.com>
---
 tools/build/Makefile.build | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/build/Makefile.build b/tools/build/Makefile.build
index 3584ff308607..39066a3ef2fc 100644
--- a/tools/build/Makefile.build
+++ b/tools/build/Makefile.build
@@ -70,11 +70,13 @@ quiet_cmd_gen = GEN     $@
 # If there's nothing to link, create empty $@ object.
 quiet_cmd_ld_multi = LD      $@
       cmd_ld_multi = $(if $(strip $(obj-y)),\
-                     $(LD) -r -o $@  $(filter $(obj-y),$^),rm -f $@; $(AR) rcs $@)
+                     printf "$(objprefix)%s " $(patsubst $(objprefix)%,%,$(filter $(obj-y),$^)) | \
+                     xargs $(LD) -r -o $@,rm -f $@; $(AR) rcs $@)
 
 quiet_cmd_host_ld_multi = HOSTLD  $@
       cmd_host_ld_multi = $(if $(strip $(obj-y)),\
-                          $(HOSTLD) -r -o $@  $(filter $(obj-y),$^),rm -f $@; $(HOSTAR) rcs $@)
+                          printf "$(objprefix)%s " $(patsubst $(objprefix)%,%,$(filter $(obj-y),$^)) | \
+                          xargs $(HOSTLD) -r -o $@,rm -f $@; $(HOSTAR) rcs $@)
 
 ifneq ($(filter $(obj),$(hostprogs)),)
   host = host_
-- 
2.34.1