[glib] meson: fix 'Unknown variable "gtester"' error on windows

[Tim-Philipp Müller <tpm src gnome org>]

commit 9306ada4fdd2c00813c7ea088cd6fb5003ccd352
Author: Tim-Philipp Müller <tim centricular com>
Date:   Sat Jul 15 11:21:57 2017 +0100

    meson: fix 'Unknown variable "gtester"' error on windows
    
    With msys64/mingw.

 glib/tests/meson.build |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/glib/tests/meson.build b/glib/tests/meson.build
index 6b7e323..f11869e 100644
--- a/glib/tests/meson.build
+++ b/glib/tests/meson.build
@@ -169,7 +169,7 @@ executable('test-spawn-echo', 'test-spawn-echo.c',
 )
 
 # some testing of gtester functionality
-if not meson.is_cross_build() and meson.version().version_compare('> 0.37.9')
+if not meson.is_cross_build() and host_system != 'windows'
   xmllint = find_program('xmllint')
   if xmllint.found()
     tmpsample_xml = custom_target('tmpsample.xml',