Remove optimized code for bzero, which was removed from POSIX in 2008.

I'll come back for the last bcopy remnant...

Bug: http://b/26407170
Change-Id: Iabfeb95fc8a4b4b3992e3cc209ec5221040e7c26
diff --git a/libc/bionic/ndk_cruft.cpp b/libc/bionic/ndk_cruft.cpp
index 3ac88f8..6dc233a 100644
--- a/libc/bionic/ndk_cruft.cpp
+++ b/libc/bionic/ndk_cruft.cpp
@@ -250,6 +250,12 @@
 // x86 has an assembler implementation.
 #endif
 
+// This was removed from POSIX 2008.
+#undef bzero
+void bzero(void* dst, size_t n) {
+  memset(dst, 0, n);
+}
+
 // sysv_signal() was never in POSIX.
 extern "C++" sighandler_t _signal(int signum, sighandler_t handler, int flags);
 sighandler_t sysv_signal(int signum, sighandler_t handler) {