merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/ci/run-build-and-tests.sh

@@ -0,0 +1,37 @@
+#!/bin/sh
+#
+# Build and test Git
+#
+
+. ${0%/*}/lib.sh
+
+case "$CI_OS_NAME" in
+windows*) cmd //c mklink //j t\\.prove "$(cygpath -aw "$cache_dir/.prove")";;
+*) ln -s "$cache_dir/.prove" t/.prove;;
+esac
+
+make
+case "$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
+	;;
+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
+
+save_good_tree