[PATCH 03/46] kbuild: lto: preserve MAKEFLAGS for module linking

[Jiri Slaby (SUSE)]

From: Martin Liska <mliska@xxxxxxx>

Prefix cc_o_c and ld_multi_m commands in makefile in order to preserve
access to jobserver. This is needed for gcc LTO at least (enabled in
later patches in this series). Note that both commands can invoke the
linker (ld_single_m in the former case).

Fixes this warning:
lto-wrapper: warning: jobserver is not available: ‘--jobserver-auth=’ is not present in ‘MAKEFLAGS’

Cc: Sedat Dilek <sedat.dilek@xxxxxxxxx>
Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Cc: Michal Marek <michal.lkml@xxxxxxxxxxx>
Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Fixes: 5d45950dfbb1 (kbuild: move vmlinux.o link to scripts/Makefile.vmlinux_o)
Signed-off-by: Martin Liska <mliska@xxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 scripts/Makefile.build | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 41f3602fc8de..564a20ce2667 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -247,7 +247,7 @@ endef
 
 # Built-in and composite module parts
 $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
-	$(call if_changed_rule,cc_o_c)
+	+$(call if_changed_rule,cc_o_c)
 	$(call cmd,force_checksrc)
 
 # To make this rule robust against "Argument list too long" error,
@@ -457,7 +457,7 @@ endef
 $(multi-obj-m): objtool-enabled := $(delay-objtool)
 $(multi-obj-m): part-of-module := y
 $(multi-obj-m): %.o: %.mod FORCE
-	$(call if_changed_rule,ld_multi_m)
+	+$(call if_changed_rule,ld_multi_m)
 $(call multi_depend, $(multi-obj-m), .o, -objs -y -m)
 
 # Add intermediate targets:
-- 
2.38.1