configure: move X11 detection to Meson

For now move the logic verbatim.  GTK+ actually has a hard requirement
on X11 if gtk+x11 is present, but we will sort that out later.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -2759,14 +2759,6 @@ EOF
   fi
 fi
 
-##########################################
-# X11 probe
-if $pkg_config --exists "x11"; then
-    have_x11=yes
-    x11_cflags=$($pkg_config --cflags x11)
-    x11_libs=$($pkg_config --libs x11)
-fi
-
 ##########################################
 # GTK probe
 
@@ -5681,10 +5673,8 @@ fi
 if test "$module_upgrades" = "yes"; then
   echo "CONFIG_MODULE_UPGRADES=y" >> $config_host_mak
 fi
-if test "$have_x11" = "yes" && test "$need_x11" = "yes"; then
-  echo "CONFIG_X11=y" >> $config_host_mak
-  echo "X11_CFLAGS=$x11_cflags" >> $config_host_mak
-  echo "X11_LIBS=$x11_libs" >> $config_host_mak
+if test "$need_x11" = "yes"; then
+  echo "CONFIG_NEED_X11=y" >> $config_host_mak
 fi
 if test "$pipe2" = "yes" ; then
   echo "CONFIG_PIPE2=y" >> $config_host_mak

meson.build

@@ -787,9 +787,9 @@ if 'CONFIG_VTE' in config_host
                            link_args: config_host['VTE_LIBS'].split())
 endif
 x11 = not_found
-if 'CONFIG_X11' in config_host
-  x11 = declare_dependency(compile_args: config_host['X11_CFLAGS'].split(),
-                           link_args: config_host['X11_LIBS'].split())
+if config_host.has_key('CONFIG_NEED_X11')
+  x11 = dependency('x11', method: 'pkg-config', required: false,
+                   static: enable_static)
 endif
 vnc = not_found
 png = not_found
@@ -1085,6 +1085,7 @@ config_host_data.set('CONFIG_STATX', has_statx)
 config_host_data.set('CONFIG_ZSTD', zstd.found())
 config_host_data.set('CONFIG_FUSE', fuse.found())
 config_host_data.set('CONFIG_FUSE_LSEEK', fuse_lseek.found())
+config_host_data.set('CONFIG_X11', x11.found())
 config_host_data.set('CONFIG_CFI', get_option('cfi'))
 config_host_data.set('QEMU_VERSION', '"@0@"'.format(meson.project_version()))
 config_host_data.set('QEMU_VERSION_MAJOR', meson.project_version().split('.')[0])
@@ -1171,7 +1172,7 @@ host_kconfig = \
   ('CONFIG_SPICE' in config_host ? ['CONFIG_SPICE=y'] : []) + \
   ('CONFIG_IVSHMEM' in config_host ? ['CONFIG_IVSHMEM=y'] : []) + \
   ('CONFIG_OPENGL' in config_host ? ['CONFIG_OPENGL=y'] : []) + \
-  ('CONFIG_X11' in config_host ? ['CONFIG_X11=y'] : []) + \
+  (x11.found() ? ['CONFIG_X11=y'] : []) + \
   ('CONFIG_VHOST_USER' in config_host ? ['CONFIG_VHOST_USER=y'] : []) + \
   ('CONFIG_VHOST_VDPA' in config_host ? ['CONFIG_VHOST_VDPA=y'] : []) + \
   ('CONFIG_VHOST_KERNEL' in config_host ? ['CONFIG_VHOST_KERNEL=y'] : []) + \

ui/meson.build

@@ -62,7 +62,7 @@ if config_host.has_key('CONFIG_GTK')
 
   gtk_ss = ss.source_set()
   gtk_ss.add(gtk, vte, pixman, files('gtk.c'))
-  gtk_ss.add(when: [x11, 'CONFIG_X11'], if_true: files('x_keymap.c'))
+  gtk_ss.add(when: x11, if_true: files('x_keymap.c'))
   gtk_ss.add(when: [opengl, 'CONFIG_OPENGL'], if_true: files('gtk-egl.c', 'gtk-gl-area.c'))
   ui_modules += {'gtk' : gtk_ss}
 endif
@@ -77,7 +77,7 @@ if sdl.found()
     'sdl2.c',
   ))
   sdl_ss.add(when: [opengl, 'CONFIG_OPENGL'], if_true: files('sdl2-gl.c'))
-  sdl_ss.add(when: [x11, 'CONFIG_X11'], if_true: files('x_keymap.c'))
+  sdl_ss.add(when: x11, if_true: files('x_keymap.c'))
   ui_modules += {'sdl' : sdl_ss}
 endif