Reland "Retire GCC FORTIFY."

This reverts commit 4dbe8fc22f96868d3e5164653a6387b86b163673.

The angler/bullhead builds are now dead, so this can go in.

Bug: https://issuetracker.google.com/74404306
Change-Id: I130cdcd6375b6125cb8a1e63a4a540b0dbe41ceb
diff --git a/libc/include/sys/mman.h b/libc/include/sys/mman.h
index 5a7e3c0..4073fbf 100644
--- a/libc/include/sys/mman.h
+++ b/libc/include/sys/mman.h
@@ -56,14 +56,7 @@
  * preserve the old behavior for GCC and emit a useful diagnostic.
  */
 #if defined(__USE_FILE_OFFSET64)
-void* mmap(void* __addr, size_t __size, int __prot, int __flags, int __fd, off_t __offset)
-#  if !defined(__clang__) && __ANDROID_API__ < __ANDROID_API_L__
-      __attribute__((error("mmap is not available with _FILE_OFFSET_BITS=64 when using GCC until "
-                           "android-21. Either raise your minSdkVersion, disable "
-                           "_FILE_OFFSET_BITS=64, or switch to Clang.")));
-#  else
-    __RENAME(mmap64);
-#  endif
+void* mmap(void* __addr, size_t __size, int __prot, int __flags, int __fd, off_t __offset) __RENAME(mmap64);
 #else
 void* mmap(void* __addr, size_t __size, int __prot, int __flags, int __fd, off_t __offset);
 #endif