New subdirectory system-tests.

New subdirectory system-tests.

* gettext-tools/system-tests/Makefile.am: New file.
* gettext-tools/system-tests/README: New file.
* gettext-tools/system-tests/run-test: New file.
* gettext-tools/system-tests/testlocale.c: New file.
* gettext-tools/system-tests/intl-1-prg.c: New file.
* gettext-tools/system-tests/intl-3-prg.c: New file.
* gettext-tools/system-tests/intl-4-prg.c: New file.
* gettext-tools/system-tests/intl-5-prg.c: New file.
* gettext-tools/system-tests/intl-setlocale-1-prg.c: New file.
* gettext-tools/system-tests/intl-setlocale-2-prg.c: New file.
* gettext-tools/system-tests/intl-thread-1-prg.c: New file.
* gettext-tools/system-tests/intl-thread-2-prg.c: New file.
* gettext-tools/system-tests/intl-thread-3-prg.c: New file.
* gettext-tools/system-tests/format-c-3-prg.c: New file.
* gettext-tools/system-tests/format-c-4-prg.c: New file.
* gettext-tools/system-tests/format-c-5-prg.c: New file.
* gettext-tools/system-tests/plural-1-prg.c: New file.
* gettext-tools/Makefile.am (SUBDIRS): Add system-tests.
* gettext-tools/configure.ac (TEST_SYSTEM_LIBINTL): New conditional.
(AC_CONFIG_FILES): Add system-tests/Makefile.
* gettext-tools/tests/init.cfg: Include init-env from the tests/ directory.
* gettext-tools/tests/intl-5-prg.c: When USE_SYSTEM_LIBINTL is defined, use the
system's <libintl.h>.
* gettext-tools/tests/intl-setlocale-1-prg.c: Likewise.
* gettext-tools/tests/intl-setlocale-2-prg.c: Likewise.
* gettext-tools/tests/intl-thread-1-prg.c: Likewise.
* gettext-tools/tests/intl-thread-2-prg.c: Likewise.
* gettext-tools/tests/intl-thread-3-prg.c: Likewise.
* gettext-tools/tests/intl-1-prg.c: When USE_SYSTEM_LIBINTL is defined, use the
system's <libintl.h>.
* gettext-tools/tests/intl-3-prg.c: Likewise.
* gettext-tools/tests/intl-4-prg.c: Likewise.
* gettext-tools/tests/format-c-3-prg.c: Likewise.
* gettext-tools/tests/format-c-4-prg.c: Likewise.
* gettext-tools/tests/plural-1-prg.c: Likewise.
* gettext-tools/tests/format-c-5-prg.c: When USE_SYSTEM_LIBINTL is defined, use
the system's <libintl.h> and setenv instead of xsetenv, and no fake setlocale.
* gettext-tools/tests/format-c-3: When USE_SYSTEM_LIBINTL is defined, try
$LOCALE_FR and $LOCALE_FR_UTF8.
* gettext-tools/tests/format-c-4: Likewise.
* gettext-tools/tests/plural-1: Likewise.
* gettext-tools/tests/format-c-5: When USE_SYSTEM_LIBINTL is defined, try fa_IR
and fa_IR.UTF-8.