<sched.h> should offer both __sched_priority and sched_priority.

If glibc hadn't already done things this way round, I'd have
called the field sched_priority and the macro __sched_priority
since that would seem less likely to cause trouble, but glibc
source compatibility is probably more important.

Change-Id: I8a8a477f2aa87cae641069c5c84b4fcab3152a82

libc/include/sched.h

@@ -39,8 +39,9 @@ __BEGIN_DECLS
 #define SCHED_OTHER SCHED_NORMAL
 
 struct sched_param {
-  int sched_priority;
+  int __sched_priority;
 };
+#define sched_priority __sched_priority
 
 extern int sched_setscheduler(pid_t, int, const struct sched_param*);
 extern int sched_getscheduler(pid_t);