[PATCH v2 3/3] objtool: use global host flags for compilation

[Robin Jarry]

When libelf headers and libs are not found and CONFIG_UNWINDER_ORC is
selected, there is a make error introduced by
commit 3dd40cb320fe ("objtool: Upgrade libelf-devel warning to error for
CONFIG_ORC_UNWINDER").

Host headers and libs may be in a non-standard location and the check is
performed without host flags. Make sure to use host flags for the check
and for building objtool. Remove duplicate flags.

Fixes: 3b27a0c85d70 ("objtool: Detect and warn if libelf is missing and don't break the build")
Signed-off-by: Robin Jarry <robin.jarry@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
---
 Makefile               | 2 +-
 tools/objtool/Makefile | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index f7c543cebfc6..c9dc35fe0e48 100644
--- a/Makefile
+++ b/Makefile
@@ -955,7 +955,7 @@ export mod_sign_cmd
 
 ifdef CONFIG_STACK_VALIDATION
   has_libelf := $(call try-run,\
-		echo "int main() {}" | $(HOSTCC) -xc -o /dev/null -lelf -,1,0)
+	echo "int main() {}" | $(HOSTCC) $(HOSTLDFLAGS) -xc -o /dev/null -lelf -,1,0)
   ifeq ($(has_libelf),1)
     objtool_target := tools/objtool FORCE
   else
diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index e6acc281dd37..4d4b810313e2 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -31,8 +31,8 @@ INCLUDES := -I$(srctree)/tools/include \
 	    -I$(srctree)/tools/arch/$(HOSTARCH)/include/uapi \
 	    -I$(srctree)/tools/objtool/arch/$(ARCH)/include
 WARNINGS := $(EXTRA_WARNINGS) -Wno-switch-default -Wno-switch-enum -Wno-packed
-CFLAGS   += -Wall -Werror $(WARNINGS) -fomit-frame-pointer -O2 -g $(INCLUDES)
-LDFLAGS  += -lelf $(LIBSUBCMD)
+CFLAGS   += $(HOSTCFLAGS) -Werror $(WARNINGS) -g $(INCLUDES)
+LDFLAGS  += $(HOSTLDFLAGS) -lelf $(LIBSUBCMD)
 
 # Allow old libelf to be used:
 elfshdr := $(shell echo '\#include <libelf.h>' | $(CC) $(CFLAGS) -x c -E - | grep elf_getshdr)
-- 
2.11.0