[gimp] build/win: Clear DISPLAY before building.

[Michael Henning <mhenning src gnome org>]

commit c52ec55f3a4e995b184908f50b6662f74f4c4d69
Author: Michael Henning <drawoc darkrefraction com>
Date:   Sat Jun 4 13:29:42 2016 -0400

    build/win: Clear DISPLAY before building.

 build/windows/jhbuild/build.jhbuildrc |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/build/windows/jhbuild/build.jhbuildrc b/build/windows/jhbuild/build.jhbuildrc
index 9b60a71..ea5cc4a 100644
--- a/build/windows/jhbuild/build.jhbuildrc
+++ b/build/windows/jhbuild/build.jhbuildrc
@@ -77,6 +77,9 @@ if os.environ.get('MINGW_USE_CCACHE', '') == 'yes':
     os.environ['CPP'] = 'ccache ' + os.environ['CPP']
     os.environ['CXX'] = 'ccache ' + os.environ['CXX']
 
+# Clear DISPLAY (prevents wine from popping up dialogs on some machines)
+os.environ['DISPLAY'] = ''
+
 #Added another common env var name for windres
 os.environ['RC'] = os.environ['WINDRES']