[X86] Add 'fxsr' to the getHostCPUFeatures detection code.

We implicitly mark this feature as enabled when the target is 64-bits, but our detection code for -march=native didn't support it so you can't detect it on 32-bit targets.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@353963 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Host.cpp b/lib/Support/Host.cpp
index 1b907bc..367fd18 100644
--- a/lib/Support/Host.cpp
+++ b/lib/Support/Host.cpp
@@ -1259,6 +1259,7 @@
 
   Features["cmov"]   = (EDX >> 15) & 1;
   Features["mmx"]    = (EDX >> 23) & 1;
+  Features["fxsr"]   = (EDX >> 24) & 1;
   Features["sse"]    = (EDX >> 25) & 1;
   Features["sse2"]   = (EDX >> 26) & 1;