LibC: Make spawn.h parse in C files

Author: https://github.com/nico
Commit: 68f281c864
Pull-request: https://github.com/SerenityOS/serenity/pull/2591
Reviewed-by: https://github.com/alimpfard
Reviewed-by: https://github.com/awesomekling

Libraries/LibC/spawn.h

@@ -59,7 +59,7 @@ typedef struct {
 typedef struct {
     short flags;
     pid_t pgroup;
-    sched_param schedparam;
+    struct sched_param schedparam;
     int schedpolicy;
     sigset_t sigdefault;
     sigset_t sigmask;