[Driver] Use --warn-shared-textrel for Android.

Android does not allow shared text relocations. Enable the linker
warning to detect them by default.

Reviewers: srhines, pirama

Reviewed By: srhines

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D53344

llvm-svn: 357296
diff --git a/clang/lib/Driver/ToolChains/Gnu.cpp b/clang/lib/Driver/ToolChains/Gnu.cpp
index 7b2dd67..9663b51 100644
--- a/clang/lib/Driver/ToolChains/Gnu.cpp
+++ b/clang/lib/Driver/ToolChains/Gnu.cpp
@@ -387,6 +387,11 @@
       CmdArgs.push_back("--fix-cortex-a53-843419");
   }
 
+  // Android does not allow shared text relocations. Emit a warning if the
+  // user's code contains any.
+  if (isAndroid)
+      CmdArgs.push_back("--warn-shared-textrel");
+
   for (const auto &Opt : ToolChain.ExtraOpts)
     CmdArgs.push_back(Opt.c_str());