Add Hurd target to LLVMSupport (1/2)

Add the required target triples to LLVMSupport to support Hurd
in LLVM (formally `pc-hurd-gnu`).

Patch by sthibaul (Samuel Thibault)

Differential Revision: https://reviews.llvm.org/D54378

llvm-svn: 347832
diff --git a/llvm/unittests/ADT/TripleTest.cpp b/llvm/unittests/ADT/TripleTest.cpp
index 71a922a..efe859f 100644
--- a/llvm/unittests/ADT/TripleTest.cpp
+++ b/llvm/unittests/ADT/TripleTest.cpp
@@ -93,6 +93,12 @@
   EXPECT_EQ(Triple::Contiki, T.getOS());
   EXPECT_EQ(Triple::UnknownEnvironment, T.getEnvironment());
 
+  T = Triple("i386-pc-hurd-gnu");
+  EXPECT_EQ(Triple::x86, T.getArch());
+  EXPECT_EQ(Triple::PC, T.getVendor());
+  EXPECT_EQ(Triple::Hurd, T.getOS());
+  EXPECT_EQ(Triple::GNU, T.getEnvironment());
+
   T = Triple("x86_64-pc-linux-gnu");
   EXPECT_EQ(Triple::x86_64, T.getArch());
   EXPECT_EQ(Triple::PC, T.getVendor());