51 pkgconfig-gen: Disable validation on Windows

The pkg-config version shipped with MinGW is too old, and the test is
sufficiently covered on Linux, so just skip it on Windows. We anyway do
not run the other pkg-config tests on Windows.

test cases/common/51 pkgconfig-gen/meson.build

@@ -19,7 +19,7 @@ pkgg.generate(
 )
 
 pkgconfig = find_program('pkg-config', required: false)
-if pkgconfig.found()
+if pkgconfig.found() and build_machine.system() != 'windows'
   test('pkgconfig-validation', pkgconfig,
     args: ['--validate', 'simple'],
     env: ['PKG_CONFIG_PATH=' + meson.current_build_dir() + '/meson-private' ],