travis: build and test on Linux with musl libc and busybox

Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

.travis.yml

@@ -33,6 +33,14 @@ matrix:
         - docker
       before_install:
       script: ci/run-docker.sh
+    - env: jobname=linux-musl
+      os: linux
+      compiler:
+      addons:
+      services:
+        - docker
+      before_install:
+      script: ci/run-docker.sh
     - env: jobname=StaticAnalysis
       os: linux
       compiler:

ci/install-docker-dependencies.sh

@@ -11,4 +11,8 @@ Linux32)
 			libssl-dev libexpat-dev gettext python >/dev/null
 	'
 	;;
+linux-musl)
+	apk add --update build-base curl-dev openssl-dev expat-dev gettext \
+		pcre2-dev python3 musl-libintl perl-utils ncurses >/dev/null
+	;;
 esac

ci/lib.sh

@@ -195,6 +195,11 @@ GIT_TEST_GETTEXT_POISON)
 Linux32)
 	CC=gcc
 	;;
+linux-musl)
+	CC=gcc
+	MAKEFLAGS="$MAKEFLAGS PYTHON_PATH=/usr/bin/python3 USE_LIBPCRE2=Yes"
+	MAKEFLAGS="$MAKEFLAGS NO_REGEX=Yes ICONV_OMITS_BOM=Yes"
+	;;
 esac
 
 MAKEFLAGS="$MAKEFLAGS CC=${CC:-cc}"

ci/run-docker-build.sh

@@ -18,6 +18,10 @@ case "$jobname" in
 Linux32)
 	switch_cmd="linux32 --32bit i386"
 	;;
+linux-musl)
+	switch_cmd=
+	useradd () { adduser -D "$@"; }
+	;;
 *)
 	exit 1
 	;;

ci/run-docker.sh

@@ -9,6 +9,9 @@ case "$jobname" in
 Linux32)
 	CI_CONTAINER="daald/ubuntu32:xenial"
 	;;
+linux-musl)
+	CI_CONTAINER=alpine
+	;;
 *)
 	exit 1
 	;;