kbuild: userprogs: use correct linker when mixing clang and GNU ld

commit 936599ca514973d44a766b7376c6bbdc96b6a8cc upstream.

The userprogs infrastructure does not expect clang being used with GNU ld
and in that case uses /usr/bin/ld for linking, not the configured $(LD).
This fallback is problematic as it will break when cross-compiling.
Mixing clang and GNU ld is used for example when building for SPARC64,
as ld.lld is not sufficient; see Documentation/kbuild/llvm.rst.

Relax the check around --ld-path so it gets used for all linkers.

Fixes: dfc1b16 ("kbuild: userprogs: use correct lld when linking through clang")
Cc: [email protected]
Signed-off-by: Thomas Weißschuh <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
Signed-off-by: Masahiro Yamada <[email protected]>
[nathan: Work around wrapping '--ld-path' in cc-option in older stable
         branches due to older minimum LLVM version]
Signed-off-by: Nathan Chancellor <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
(cherry picked from commit 0ed2068de1f9afdde56436af91aba8cbb77c2741)

Author: t-8ch

Makefile

@@ -1071,7 +1071,7 @@ KBUILD_USERCFLAGS  += $(filter -m32 -m64 --target=%, $(KBUILD_CPPFLAGS) $(KBUILD
 KBUILD_USERLDFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))
 
 # userspace programs are linked via the compiler, use the correct linker
-ifeq ($(CONFIG_CC_IS_CLANG)$(CONFIG_LD_IS_LLD),yy)
+ifdef CONFIG_CC_IS_CLANG
 KBUILD_USERLDFLAGS += $(call cc-option, --ld-path=$(LD))
 endif