LinGUI: Remove update checker

The update checker didn't work and could not be built on any recent
Linux distribution. Linux updates are handled by Flatpak or the
distribution.
configure.py will error out if the --disable-gtk-update-checks
flag is used. This is to avoid the flag being passed to make and
giving an error anyway.

.github/workflows/linux.yml

@@ -55,4 +55,4 @@ jobs:
       run: |
          PWD=$(pwd)
          export PATH=$PWD/cmake-3.16.3-Linux-x86_64/bin:$PATH
-         ./configure --disable-gtk-update-checks --enable-qsv --enable-vce --enable-nvenc --enable-nvdec --launch-jobs=0 --launch
+         ./configure --enable-qsv --enable-vce --enable-nvenc --enable-nvdec --launch-jobs=0 --launch

gtk/configure.ac

@@ -101,10 +101,6 @@ AC_ARG_ENABLE(gst,
 	AS_HELP_STRING([--disable-gst], [disable gstreamer (live preview)]),
 	gst_disable=yes, gst_disable=no)
 
-AC_ARG_ENABLE(update-checks,
-	AS_HELP_STRING([--disable-update-checks], [disable update checks]),
-	update_checks=no, update_checks=yes)
-
 AC_ARG_ENABLE(gtk4,
 	AS_HELP_STRING([--enable-gtk4], [enable building with gtk4]),
 	use_gtk4=yes, use_gtk4=no)
@@ -195,19 +191,6 @@ if test "x$gst_disable" = "xno" ; then
 	CFLAGS="$CFLAGS -D_ENABLE_GST"
 fi
 
-if test "x$update_checks" = "xyes" ; then
-	PKG_CHECK_MODULES([webkitgtk], webkitgtk-3.0, use_webkitgtk=yes, use_webkitgtk=no)
-	if test "x$use_webkitgtk" = "xyes" ; then
-		HB_LIBS="$HB_LIBS $webkitgtk_LIBS"
-		HB_CPPFLAGS="$HB_CPPFLAGS $webkitgtk_CFLAGS"
-	else
-		update_checks="no"
-		CFLAGS="$CFLAGS -D_NO_UPDATE_CHECK"
-	fi
-else
-	CFLAGS="$CFLAGS -D_NO_UPDATE_CHECK"
-fi
-
 AM_CONDITIONAL([GHB_GTK_4_4], [test "$HAVE_GTK_4_4" -eq 1])
 AM_CONDITIONAL([GHB_GTK_3_22], [test "$HAVE_GTK_3_22" -eq 1])
 

gtk/module.defs

@@ -28,10 +28,6 @@ ifeq ($(HAS.pthread),1)
 endif
 endif
 
-ifeq (0,$(FEATURE.gtk.update.checks))
-	GTK.CONFIGURE.extra += --disable-update-checks
-endif
-
 ifeq (0,$(FEATURE.gst))
 	GTK.CONFIGURE.extra += --disable-gst
 endif

gtk/src/Makefile.am

@@ -105,8 +105,6 @@ ghb_SOURCES = \
 	icons.h \
 	values.c \
 	values.h \
-	appcast.c \
-	appcast.h \
 	plist.c \
 	plist.h \
 	hb-backend.c \