Add fopen64/freopen64/tmpfile64 aliases.

Our fopen/freopen/tmpfile are already always O_LARGEFILE, but let's add
the aliases for _LARGEFILE_SOURCE compatibility.

Bug: http://b/24807045
Change-Id: I5d99b3ef3c9f27ce70f13313f6a92e96c7f21f80
diff --git a/libc/stdio/stdio.cpp b/libc/stdio/stdio.cpp
index 16cbd55..1c31a27 100644
--- a/libc/stdio/stdio.cpp
+++ b/libc/stdio/stdio.cpp
@@ -222,6 +222,7 @@
 
   return fp;
 }
+__strong_alias(fopen64, fopen);
 
 FILE* fdopen(int fd, const char* mode) {
   int oflags;
@@ -358,6 +359,7 @@
   if (oflags & O_APPEND) __sseek64(fp, 0, SEEK_END);
   return fp;
 }
+__strong_alias(freopen64, freopen);
 
 int fclose(FILE* fp) {
   if (fp->_flags == 0) {