Clean up <stdlib.h> slightly.

Interestingly, this mostly involves cleaning up our implementation of
various <string.h> functions.

Change-Id: Ifaef49b5cb997134f7bc0cc31bdac844bdb9e089
diff --git a/libc/bionic/ndk_cruft.cpp b/libc/bionic/ndk_cruft.cpp
index 18a4a14..341ba01 100644
--- a/libc/bionic/ndk_cruft.cpp
+++ b/libc/bionic/ndk_cruft.cpp
@@ -235,6 +235,12 @@
   return signal(signum, handler);
 }
 
+// This was removed from POSIX 2008.
+#undef bcopy
+extern "C" void bcopy(const void* src, void* dst, size_t n) {
+  memcpy(dst, src, n);
+}
+
 // sysv_signal() was never in POSIX.
 extern sighandler_t _signal(int signum, sighandler_t handler, int flags);
 extern "C" sighandler_t sysv_signal(int signum, sighandler_t handler) {