This patch fixes problem

https://trac.macports.org/ticket/54962
in upstream: https://bugzilla.gnome.org/show_bug.cgi?id=788401

The problem is that in a quartz build the gdk-pixbuf cannot identify
the content type just from data because the xdgmime system is not used.
This patch is not applied during macports patch phase. But this patch
is the root change which will then change gio/Makefile.in with autoreconf.
The change due to autoreconf on gio/Makefile.in is recorded in:

patch-gio-quartz-makefilein-generated.diff

In addition the patch

patch-gio-quartz-gosxcontenttype.diff

has to be applied.

--- gio/Makefile.am.orig	2017-10-02 01:13:46.000000000 +0200
+++ gio/Makefile.am	2017-10-02 01:14:04.000000000 +0200
@@ -3,14 +3,8 @@
 SUBDIRS = gdbus-2.0/codegen
 
 if OS_UNIX
-if OS_COCOA
-if APPINFO_IMPL_GENERIC
-SUBDIRS += xdgmime
-endif
-else
 SUBDIRS += xdgmime
 endif
-endif
 
 if OS_WIN32_AND_DLL_COMPILATION
 if MS_LIB_AVAILABLE
@@ -259,19 +253,12 @@
 if APPINFO_IMPL_NATIVE
 appinfo_headers += gosxappinfo.h
 else
-platform_libadd += xdgmime/libxdgmime.la
-platform_deps += xdgmime/libxdgmime.la
-
 appinfo_headers += gdesktopappinfo.h
 endif
-else
+endif
 platform_libadd += xdgmime/libxdgmime.la
 platform_deps += xdgmime/libxdgmime.la
 
-appinfo_headers += gdesktopappinfo.h
-endif
-
-
 unix_sources = \
 	gfiledescriptorbased.c  \
 	gunixconnection.c	\
