spice: Add missing 'static' attribute

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
diff --git a/spice-qemu-char.c b/spice-qemu-char.c
index 7e0d300..a4f4e57 100644
--- a/spice-qemu-char.c
+++ b/spice-qemu-char.c
@@ -158,7 +158,7 @@
     return func(NULL, G_IO_OUT, user_data);
 }
 
-GSourceFuncs SpiceCharSourceFuncs = {
+static GSourceFuncs SpiceCharSourceFuncs = {
     .prepare  = spice_char_source_prepare,
     .check    = spice_char_source_check,
     .dispatch = spice_char_source_dispatch,