test-lib: use DIFF definition from GIT-BUILD-OPTIONS

Otherwise running individual tests from t/ directory may lack the definition
of $DIFF, $GIT_TEST_CMP and friends.

Noticed and initial patch provided by Thomas Rast, alternative solution
suggested by Brandon Casey, which this patch implements.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Acked-by: Thomas Rast <trast@student.ethz.ch>

Makefile

@@ -1944,6 +1944,12 @@ GIT-BUILD-OPTIONS: FORCE
 	@echo NO_CURL=\''$(subst ','\'',$(subst ','\'',$(NO_CURL)))'\' >>$@
 	@echo NO_PERL=\''$(subst ','\'',$(subst ','\'',$(NO_PERL)))'\' >>$@
 	@echo NO_PYTHON=\''$(subst ','\'',$(subst ','\'',$(NO_PYTHON)))'\' >>$@
+ifdef GIT_TEST_CMP
+	@echo GIT_TEST_CMP=\''$(subst ','\'',$(subst ','\'',$(GIT_TEST_CMP)))'\' >>$@
+endif
+ifdef GIT_TEST_CMP_USE_COPIED_CONTEXT
+	@echo GIT_TEST_CMP_USE_COPIED_CONTEXT=YesPlease >>$@
+endif
 
 ### Detect Tck/Tk interpreter path changes
 ifndef NO_TCLTK

t/test-lib.sh

@@ -64,16 +64,6 @@ export GIT_AUTHOR_EMAIL GIT_AUTHOR_NAME
 export GIT_COMMITTER_EMAIL GIT_COMMITTER_NAME
 export EDITOR
 
-if test -z "$GIT_TEST_CMP"
-then
-	if test -n "$GIT_TEST_CMP_USE_COPIED_CONTEXT"
-	then
-		GIT_TEST_CMP="$DIFF -c"
-	else
-		GIT_TEST_CMP="$DIFF -u"
-	fi
-fi
-
 # Protect ourselves from common misconfiguration to export
 # CDPATH into the environment
 unset CDPATH
@@ -691,6 +681,16 @@ export PATH GIT_EXEC_PATH GIT_TEMPLATE_DIR GIT_CONFIG_NOSYSTEM GIT_CONFIG_NOGLOB
 
 . ../GIT-BUILD-OPTIONS
 
+if test -z "$GIT_TEST_CMP"
+then
+	if test -n "$GIT_TEST_CMP_USE_COPIED_CONTEXT"
+	then
+		GIT_TEST_CMP="$DIFF -c"
+	else
+		GIT_TEST_CMP="$DIFF -u"
+	fi
+fi
+
 GITPERLLIB=$(pwd)/../perl/blib/lib:$(pwd)/../perl/blib/arch/auto/Git
 export GITPERLLIB
 test -d ../templates/blt || {