When trying to build an altered rawhide kernel in F10 I get the error
cc1: warnings being treated as errors
drivers/video/console/fbcon.c: In function 'quiet_logo':
drivers/video/console/fbcon.c:3603: error: no return statement in function returning non-void
make[3]: *** [drivers/video/console/fbcon.o] Error 1
The problem code is from linux-2.6-silence-fbcon-logo.patch, and the lines +static int __init quiet_logo(char *str)
+{
+       logo_shown = FBCON_LOGO_DONTSHOW;
+}
+
+early_param("quiet", quiet_logo);
+
and the compiler is clearly worried that this is a int function but you aren't returning anything.