[Driver] Do not add -lpthread & -lrt with -static-libsan on Android

Summary:
I am not sure anyone has tried to compile an application with sanitizers on
Android with `-static-libsan`, and a recent NDK, but it fails with:
```
.../i686-linux-android/bin/ld.gold: error: cannot find -lpthread
.../i686-linux-android/bin/ld.gold: error: cannot find -lrt
```
My understanding is that both are included in Bionic and as such are not needed,
and actually error out.

So remove the addition of those two in `linkSanitizerRuntimeDeps` when dealing
with Android, and update the tests.

I am unfamiliar with the evolution of the NDK and I am not sure if this has
always been the case or if this is somewhat of a recent evolution. I'll let
Android people chime in.

Reviewers: eugenis, pirama, srhines

Reviewed By: eugenis, srhines

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D48570

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@335620 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 2 deletions

diff --git a/lib/Driver/ToolChains/CommonArgs.cpp b/lib/Driver/ToolChains/CommonArgs.cpp
index 98a36bcd83..1e093b25b9 100644
--- a/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/lib/Driver/ToolChains/CommonArgs.cpp
@@ -564,8 +564,9 @@ void tools::linkSanitizerRuntimeDeps(const ToolChain &TC,
   // Force linking against the system libraries sanitizers depends on
   // (see PR15823 why this is necessary).
   CmdArgs.push_back("--no-as-needed");
-  // There's no libpthread or librt on RTEMS.
-  if (TC.getTriple().getOS() != llvm::Triple::RTEMS) {
+  // There's no libpthread or librt on RTEMS & Android.
+  if (TC.getTriple().getOS() != llvm::Triple::RTEMS &&
+      !TC.getTriple().isAndroid()) {
     CmdArgs.push_back("-lpthread");
     if (TC.getTriple().getOS() != llvm::Triple::OpenBSD)
       CmdArgs.push_back("-lrt");