tests: Fix pkg-config test for multiarch binaries on multiarch systems

The test was passing fine when `bindir` was equal to `multiarch_bindir`,
but not when they differ.

For example, on a Debian system, `gio-querymodules` is installed to
`/usr/lib/x86_64-linux-gnu/glib-2.0/gio-querymodules` rather than
`/usr/bin/gio-querymodules` as it is on (say) Fedora.

This was causing the pkg-config tests to fail on Debian.

Signed-off-by: Philip Withnall <pwithnall@endlessos.org>

Fixes: #3045

gio/tests/meson.build

@@ -1127,14 +1127,16 @@ if have_bash and have_pkg_config
 
   gio_binaries = [
     'gio',
-    'gio-querymodules',
-    'glib-compile-schemas',
     'glib-compile-resources',
     'gdbus',
     'gdbus-codegen',
     'gresource',
     'gsettings',
   ]
+  gio_multiarch_binaries = [
+    'gio-querymodules',
+    'glib-compile-schemas',
+  ]
 
   foreach binary: gio_binaries
     pkg_config_tests += [
@@ -1144,6 +1146,14 @@ if have_bash and have_pkg_config
     ]
   endforeach
 
+  foreach binary: gio_multiarch_binaries
+    pkg_config_tests += [
+      'test "$(pkg-config --variable=@0@ gio-2.0)" = "@1@"'.format(
+        binary.underscorify(),
+        prefix / multiarch_bindir / binary)
+    ]
+  endforeach
+
   test('gio-2.0-pkg-config',
     bash,
     args: [ '-xe', '-c', '\n'.join(pkg_config_tests) ],