Merge branch 'sg/travis-gcc-4.8'

Add a job to build with a tad older GCC to make sure we are still
buildable.

* sg/travis-gcc-4.8:
  travis-ci: build with GCC 4.8 as well

Author: gitster

.travis.yml

@@ -21,6 +21,10 @@ matrix:
       compiler:
       addons:
       before_install:
+    - env: jobname=linux-gcc-4.8
+      os: linux
+      dist: trusty
+      compiler:
     - env: jobname=Linux32
       os: linux
       compiler:

ci/run-build-and-tests.sh

@@ -11,17 +11,26 @@ windows*) cmd //c mklink //j t\\.prove "$(cygpath -aw "$cache_dir/.prove")";;
 esac
 
 make
-make test
-if test "$jobname" = "linux-gcc"
-then
+case "$jobname" in
+linux-gcc)
+	make test
 	export GIT_TEST_SPLIT_INDEX=yes
 	export GIT_TEST_FULL_IN_PACK_ARRAY=true
 	export GIT_TEST_OE_SIZE=10
 	export GIT_TEST_OE_DELTA_SIZE=5
 	export GIT_TEST_COMMIT_GRAPH=1
 	export GIT_TEST_MULTI_PACK_INDEX=1
 	make test
-fi
+	;;
+linux-gcc-4.8)
+	# Don't run the tests; we only care about whether Git can be
+	# built with GCC 4.8, as it errors out on some undesired (C99)
+	# constructs that newer compilers seem to quietly accept.
+	;;
+*)
+	make test
+	;;
+esac
 
 check_unignored_build_artifacts