[PATCH v2 1/4] init/Kconfig: add config support for detecting linker

[ndesaulniers]

Similar to how we differentiate between CONFIG_CC_IS_GCC and
CONFIG_CC_IS_CLANG, add CONFIG_LD_IS_BFD, CONFIG_LD_IS_GOLD, and
CONFIG_LD_IS_LLD.

This simiplifies patches to Makefiles that need to do different things
for different linkers.

Cc: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
Suggested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Tested-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
---
Changes V1->V2:
* Add suggested, reviewed, and tested by tags.

 init/Kconfig | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/init/Kconfig b/init/Kconfig
index c9386a365eea..b6046dcf7794 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -26,6 +26,15 @@ config CLANG_VERSION
 config CC_HAS_ASM_GOTO
 	def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC))
 
+config LD_IS_BFD
+	def_bool $(success,$(LD) --version | head -n 1 | grep -q 'GNU ld')
+
+config LD_IS_GOLD
+	def_bool $(success,$(LD) --version | head -n 1 | grep -q 'GNU gold')
+
+config LD_IS_LLD
+	def_bool $(success,$(LD) --version | head -n 1 | grep -q 'LLD')
+
 config CONSTRUCTORS
 	bool
 	depends on !UML
-- 
2.20.1.791.gb4d0f1c61a-goog