spice: flip modules switch

Build spice core code as module.  This removes libspice-server and a
handful of indirect dependencies from core qemu.  The number of shared
libraries for qemu-system-x86_64 goes down from 73 to 66 on my system.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 20201019075224.14803-13-kraxel@redhat.com

ui/meson.build

@@ -15,7 +15,6 @@ softmmu_ss.add(files(
 softmmu_ss.add([spice_headers, files('spice-module.c')])
 
 softmmu_ss.add(when: 'CONFIG_LINUX', if_true: files('input-linux.c'))
-softmmu_ss.add(when: [spice, 'CONFIG_SPICE'], if_true: files('spice-core.c', 'spice-input.c', 'spice-display.c'))
 softmmu_ss.add(when: cocoa, if_true: files('cocoa.m'))
 
 vnc_ss = ss.source_set()
@@ -71,6 +70,16 @@ if sdl.found()
   ui_modules += {'sdl' : sdl_ss}
 endif
 
+if config_host.has_key('CONFIG_SPICE')
+  spice_core_ss = ss.source_set()
+  spice_core_ss.add(spice, pixman, files(
+    'spice-core.c',
+    'spice-input.c',
+    'spice-display.c'
+  ))
+  ui_modules += {'spice-core' : spice_core_ss}
+endif
+
 if config_host.has_key('CONFIG_SPICE') and config_host.has_key('CONFIG_GIO')
   spice_ss = ss.source_set()
   spice_ss.add(spice, gio, pixman, files('spice-app.c'))