i18n module: be broadly supportive of portable gettext tools

There are a number of implementations for msgfmt, supporting various
options. The simplest, and most common, use case is to compile .po files
into .mo files, and this should be able to work on gettext
implementations other than the GNU one.

The problem is that we were passing some pretty portable arguments in an
unportable manner. The `-o` option-argument and its associated argument
came after the input file operand, which violates the POSIX Utility
Syntax Guidelines, and happens to not be supported by Solaris gettext.
The GNU gettext doesn't care; GNU invented GNU argument permutation.

Switch the order around so that our use respects the POSIX style.

mesonbuild/modules/i18n.py

@@ -285,7 +285,7 @@ class I18nModule(ExtensionModule):
                 path.join(state.subdir, l, 'LC_MESSAGES'),
                 state.subproject,
                 state.environment,
-                [self.tools['msgfmt'], '@INPUT@', '-o', '@OUTPUT@'],
+                [self.tools['msgfmt'], '-o', '@OUTPUT@', '@INPUT@'],
                 [po_file],
                 [f'{packagename}.mo'],
                 install=install,