[U-Boot] [PATCH] Makefile: remove BUILD_TAG from KBUILD_CFLAGS

[Stephen Warren]

From: Stephen Warren <swarren at nvidia.com>

If BUILD_TAG is part of KBUILD_CFLAGS, then any time the value changes,
all files get rebuilt. In a continuous integration environment, the value
will change every build. This wastes time assuming that incremental
builds would otherwise occur.

To solve this, remove BUILD_TAG from KBUILD_FLAGS and add it to the end of
"local version".

This has other advantages too:
- The special case for BUILD_TAG in display_options.c can be removed.
- The version printed by the "version" command exactly matches what is
  printed at boot.

Old sign-on message:
U-Boot 2016.03-rc1-00044-g4085db5e767b (Feb ...), Build: bar-bas

New sign-on message:
U-Boot 2016.03-rc1-00044-g4085db5e767b-bar-baz (Feb ...)

Signed-off-by: Stephen Warren <swarren at nvidia.com>
---
 Makefile                | 4 ----
 lib/display_options.c   | 4 ----
 scripts/setlocalversion | 4 ++++
 3 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/Makefile b/Makefile
index 42fad45afee1..2265b8995a7b 100644
--- a/Makefile
+++ b/Makefile
@@ -562,10 +562,6 @@ else
 KBUILD_CFLAGS	+= -O2
 endif
 
-ifdef BUILD_TAG
-KBUILD_CFLAGS += -DBUILD_TAG='"$(BUILD_TAG)"'
-endif
-
 KBUILD_CFLAGS += $(call cc-option,-fno-stack-protector)
 KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks)
 
diff --git a/lib/display_options.c b/lib/display_options.c
index 29343fc00e3f..5dcdf4e429af 100644
--- a/lib/display_options.c
+++ b/lib/display_options.c
@@ -15,11 +15,7 @@
 
 int display_options (void)
 {
-#if defined(BUILD_TAG)
-	printf ("\n\n%s, Build: %s\n\n", version_string, BUILD_TAG);
-#else
 	printf ("\n\n%s\n\n", version_string);
-#endif
 	return 0;
 }
 
diff --git a/scripts/setlocalversion b/scripts/setlocalversion
index 63d91e22ed7c..4ef6603b5c27 100755
--- a/scripts/setlocalversion
+++ b/scripts/setlocalversion
@@ -171,4 +171,8 @@ else
 	fi
 fi
 
+if test -n "${BUILD_TAG}"; then
+	res="$res-${BUILD_TAG}"
+fi
+
 echo "$res"
-- 
2.7.0