Revert "Add a hack to <stdlib.h> until we can fix libvpx."

This reverts commit 3fb5097a7eec40404760c304b36c8b657b374cab.
libvpx is now fixed.

(cherry-pick of 2be1be47aa9b63568fe6ce1e0a4029b37d90764d.)

Bug: 15598056
Change-Id: Icca974e667f92206505f484bd291726eb0150f68
diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
index 984ceb3..a5eb3d1 100644
--- a/libc/include/stdlib.h
+++ b/libc/include/stdlib.h
@@ -111,12 +111,6 @@
 
 #define RAND_MAX 0x7fffffff
 
-/* Work around x86/x86-64 libvpx build breakage caused by postproc_x86.c. */
-#if (defined(__i386__) || defined(__x86_64__)) && defined(rand)
-#undef rand
-#define __rand lrand48
-#endif
-
 int rand(void);
 int rand_r(unsigned int*);
 void srand(unsigned int);