package/python-pillow: add xcb support

libxcb is an optional dependency since version 7.1.0 and
https://github.com/python-pillow/Pillow/commit/3c39e6fcf6a11b18eec0d1c66710bcd35033d069

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/python-pillow/python-pillow.mk

@@ -35,6 +35,13 @@ else
 PYTHON_PILLOW_BUILD_OPTS += --disable-lcms
 endif
 
+ifeq ($(BR2_PACKAGE_LIBXCB),y)
+PYTHON_PILLOW_DEPENDENCIES += libxcb
+PYTHON_PILLOW_BUILD_OPTS += --enable-xcb
+else
+PYTHON_PILLOW_BUILD_OPTS += --disable-xcb
+endif
+
 ifeq ($(BR2_PACKAGE_OPENJPEG),y)
 PYTHON_PILLOW_DEPENDENCIES += openjpeg
 PYTHON_PILLOW_BUILD_OPTS += --enable-jpeg2000