ci: switch linux-musl to use Meson

Switch over the "linux-musl" job to use Meson instead of Makefiles. This
is done due to multiple reasons:

  - It simplifies our CI infrastructure a bit as we don't have to
    manually specify a couple of build options anymore.

  - It verifies that Meson detects and sets those build options
    automatically.

  - It makes it easier for us to wire up a new CI job using zlib-ng as
    backend.

One platform compatibility that Meson cannot easily detect automatically
is the `GIT_TEST_UTF8_LOCALE` variable used in tests. Wire up a build
option for it, which we set via a new "MESONFLAGS" environment variable.

Note that we also drop the CC variable, which is set to "gcc". We
already default to GCC when CC is unset in "ci/lib.sh", so this is not
needed.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

.github/workflows/main.yml

@@ -394,7 +394,7 @@ jobs:
       fail-fast: false
       matrix:
         vector:
-        - jobname: linux-musl
+        - jobname: linux-musl-meson
           image: alpine
           distro: alpine-latest
         # Supported until 2025-04-02.

.gitlab-ci.yml

@@ -67,7 +67,7 @@ test:linux:
         CC: clang
       - jobname: pedantic
         image: fedora:latest
-      - jobname: linux-musl
+      - jobname: linux-musl-meson
         image: alpine:latest
       - jobname: linux-meson
         image: ubuntu:latest

ci/install-dependencies.sh

@@ -24,7 +24,7 @@ fi
 
 case "$distro" in
 alpine-*)
-	apk add --update shadow sudo build-base curl-dev openssl-dev expat-dev gettext \
+	apk add --update shadow sudo meson ninja-build gcc libc-dev curl-dev openssl-dev expat-dev gettext \
 		pcre2-dev python3 musl-libintl perl-utils ncurses \
 		apache2 apache2-http2 apache2-proxy apache2-ssl apache2-webdav apr-util-dbd_sqlite3 \
 		bash cvs gnupg perl-cgi perl-dbd-sqlite perl-io-tty >/dev/null

ci/lib.sh

@@ -378,10 +378,7 @@ 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"
-	MAKEFLAGS="$MAKEFLAGS GIT_TEST_UTF8_LOCALE=C.UTF-8"
+	MESONFLAGS="$MESONFLAGS -DGIT_TEST_UTF8_LOCALE=C.UTF-8"
 	;;
 linux-leaks|linux-reftable-leaks)
 	export SANITIZE=leak

ci/run-build-and-tests.sh

@@ -55,7 +55,8 @@ case "$jobname" in
 		--fatal-meson-warnings \
 		--warnlevel 2 --werror \
 		--wrap-mode nofallback \
-		-Dfuzzers=true
+		-Dfuzzers=true \
+		$MESONFLAGS
 	group "Build" meson compile -C build --
 	if test -n "$run_tests"
 	then

meson.build

@@ -664,7 +664,7 @@ build_options_config.set('GIT_TEST_CMP_USE_COPIED_CONTEXT', '')
 build_options_config.set('GIT_TEST_INDEX_VERSION', '')
 build_options_config.set('GIT_TEST_OPTS', '')
 build_options_config.set('GIT_TEST_PERL_FATAL_WARNINGS', '')
-build_options_config.set('GIT_TEST_UTF8_LOCALE', '')
+build_options_config.set_quoted('GIT_TEST_UTF8_LOCALE', get_option('test_utf8_locale'))
 build_options_config.set_quoted('LOCALEDIR', fs.as_posix(get_option('prefix') / get_option('localedir')))
 build_options_config.set('GITWEBDIR', fs.as_posix(get_option('prefix') / get_option('datadir') / 'gitweb'))
 

meson_options.txt

@@ -99,5 +99,7 @@ option('tests', type: 'boolean', value: true,
   description: 'Enable building tests. This requires Perl, but is separate from the "perl" option such that you can build tests without Perl features enabled.')
 option('test_output_directory', type: 'string',
   description: 'Path to the directory used to store test outputs')
+option('test_utf8_locale', type: 'string',
+  description: 'Name of a UTF-8 locale used for testing.')
 option('fuzzers', type: 'boolean', value: false,
   description: 'Enable building fuzzers.')