Avoid including link.h.

It's not available on Android. We only use this header to find out if _DYNAMIC
is present; declaring it "extern void*" does the trick.



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@153431 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/asan/asan_linux.cc b/lib/asan/asan_linux.cc
index 40f9f94..fb2e21d 100644
--- a/lib/asan/asan_linux.cc
+++ b/lib/asan/asan_linux.cc
@@ -25,7 +25,6 @@
 #include <sys/syscall.h>
 #include <sys/types.h>
 #include <fcntl.h>
-#include <link.h>
 #include <pthread.h>
 #include <stdio.h>
 #include <unistd.h>
@@ -36,6 +35,8 @@
 #include <sys/ucontext.h>
 #endif
 
+extern "C" void* _DYNAMIC;
+
 namespace __asan {
 
 void *AsanDoesNotSupportStaticLinkage() {