libc: Add sched_yield()

libs/libc/include/sched.h

@@ -0,0 +1,16 @@
+#ifndef _SCHED_H
+#define _SCHED_H
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    /* Yield the processor. */
+    int sched_yield(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

libs/libc/src/sched.cpp

@@ -0,0 +1,11 @@
+#include <sched.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+extern "C"
+{
+    int sched_yield()
+    {
+        return (int)syscall(SYS_yield);
+    }
+}