Merge branch 'dd/svn-test-wo-locale-a'

"git-svn" tests assumed that "locale -a", which is used to pick an
available UTF-8 locale, is available everywhere.  A knob has been
introduced to allow testers to specify a suitable locale to use.

* dd/svn-test-wo-locale-a:
  t: use user-specified utf-8 locale for testing svn

ci/lib.sh

@@ -229,6 +229,7 @@ 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"
 	;;
 esac