Temporary apply LIBC version to __pthread_gettid

This is workaround for http://b/26391427

Bug: http://b/26391427
Change-Id: I4ccc56e8b1bd2597f267df9706a33bb635abcfcb
diff --git a/libc/bionic/ndk_cruft.cpp b/libc/bionic/ndk_cruft.cpp
index 4bbb2c1..1f1cd42 100644
--- a/libc/bionic/ndk_cruft.cpp
+++ b/libc/bionic/ndk_cruft.cpp
@@ -344,6 +344,9 @@
   return pthread_gettid_np(t);
 }
 
+__asm__(".symver __pthread_gettid,__pthread_gettid@LIBC");
+__asm__(".symver __pthread_gettid,__pthread_gettid@@LIBC_PRIVATE");
+
 // Older versions of apportable used dlmalloc directly instead of malloc,
 // so export this compatibility shim that simply calls malloc.
 void* dlmalloc(size_t size) {