build-sys: add gio-2.0 check

GIO is required for the "-display spice-app" backend.
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Tested-by: NVictor Toso <victortoso@redhat.com>
Message-id: 20190221110703.5775-9-marcandre.lureau@redhat.com
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

configure

@@ -3503,6 +3503,14 @@ for i in $glib_modules; do
     fi
 done
 
+if $pkg_config --atleast-version=$glib_req_ver gio-2.0; then
+    gio=yes
+    gio_cflags=$($pkg_config --cflags gio-2.0)
+    gio_libs=$($pkg_config --libs gio-2.0)
+else
+    gio=no
+fi
+
 # Sanity check that the current size_t matches the
 # size that glib thinks it should be. This catches
 # problems on multi-arch where people try to build
@@ -6520,6 +6528,11 @@ if test "$gtk" = "yes" ; then
     echo "CONFIG_GTK_GL=y" >> $config_host_mak
   fi
 fi
+if test "$gio" = "yes" ; then
+    echo "CONFIG_GIO=y" >> $config_host_mak
+    echo "GIO_CFLAGS=$gio_cflags" >> $config_host_mak
+    echo "GIO_LIBS=$gio_libs" >> $config_host_mak
+fi
 echo "CONFIG_TLS_PRIORITY=\"$tls_priority\"" >> $config_host_mak
 if test "$gnutls" = "yes" ; then
   echo "CONFIG_GNUTLS=y" >> $config_host_mak