Merge branch 'ps/meson-contrib-bits'

Update meson-based build procedure to cover contrib/ and other
places as well.

* ps/meson-contrib-bits:
  ci: exercise credential helpers
  ci: fix propagating UTF-8 test locale in musl-based Meson job
  meson: wire up static analysis via Coccinelle
  meson: wire up git-contacts(1)
  meson: wire up credential helpers
  contrib/credential: fix compilation of "osxkeychain" helper
  contrib/credential: fix compiling "libsecret" helper
  contrib/credential: fix compilation of wincred helper with MSVC
  contrib/credential: fix "netrc" tests with out-of-tree builds
  GIT-BUILD-OPTIONS: propagate project's source directory

meson.build

@@ -772,7 +772,7 @@ endif
 # features. It is optional if you want to neither execute tests nor use any of
 # these optional features.
 perl_required = get_option('perl')
-if get_option('tests') or get_option('gitweb').enabled()
+if get_option('tests') or get_option('gitweb').enabled() or 'netrc' in get_option('credential_helpers')
   perl_required = true
 endif
 
@@ -1968,10 +1968,9 @@ subdir('contrib')
 
 foreach key, value : {
   'DIFF': diff.full_path(),
+  'GIT_SOURCE_DIR': meson.project_source_root(),
   'GIT_TEST_CMP': diff.full_path() + ' -u',
   'GIT_TEST_GITPERLLIB': meson.project_build_root() / 'perl',
-  'GIT_TEST_MERGE_TOOLS_DIR': meson.project_source_root() / 'mergetools',
-  'GIT_TEST_POPATH': meson.project_source_root() / 'po',
   'GIT_TEST_TEMPLATE_DIR': meson.project_build_root() / 'templates',
   'GIT_TEST_TEXTDOMAINDIR': meson.project_build_root() / 'po',
   'PAGER_ENV': get_option('pager_environment'),