fortify: add bit checking for open(at)?64 functions

This also adds _2-variants for these functions, for extra glorious
checking

Bug: 131861088
Test: mma
Change-Id: I80475ff4bb220c0c47894e9532426f53412f176f
diff --git a/libc/bionic/open.cpp b/libc/bionic/open.cpp
index 222e5d3..df5ab21 100644
--- a/libc/bionic/open.cpp
+++ b/libc/bionic/open.cpp
@@ -70,6 +70,7 @@
   if (needs_mode(flags)) __fortify_fatal("open: called with O_CREAT/O_TMPFILE but no mode");
   return __openat(AT_FDCWD, pathname, force_O_LARGEFILE(flags), 0);
 }
+__strong_alias(__open64_2, __open_2);
 
 int openat(int fd, const char *pathname, int flags, ...) {
   mode_t mode = 0;
@@ -89,3 +90,4 @@
   if (needs_mode(flags)) __fortify_fatal("open: called with O_CREAT/O_TMPFILE but no mode");
   return __openat(fd, pathname, force_O_LARGEFILE(flags), 0);
 }
+__strong_alias(__openat64_2, __openat_2);