macx-clang: Opt-in xcb QPA support with XQuartz

Enable xcb QPA plugin when XQuartz is available. This is done
in a single build, alongside the Cocoa version.

We delegate part of the configuration stage to pkg-config, so
this becomes a requirement. Ensure that

    PKG_CONFIG_PATH=/opt/X11/lib/pkgconfig:/opt/X11/share/pkgconfig

is in your environment, or pkg-config is properly set up.

Tested with the following configure options:

configure \
   -pkg-config \
   -fontconfig -system-freetype \
   -system-xcb -xkb -no-opengl \
   -qt-xkbcommon -qt-xkbcommon-x11

Change-Id: I2eb5a0491172368afc4c629c540cbef08580348d
Reviewed-by: Jake Petroules <jake.petroules@qt.io>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/widgets/kernel/mac.pri b/src/widgets/kernel/mac.pri
index 8c694c5e05..f7e7aa869a 100644
--- a/src/widgets/kernel/mac.pri
+++ b/src/widgets/kernel/mac.pri
@@ -1,4 +1,4 @@
-!x11:osx {
+macos {
    LIBS_PRIVATE += -framework AppKit -lz
    *-mwerks:INCLUDEPATH += compat
 }