clang-3.6 build failure

[Lawrence Velázquez]

In the interest of thoroughness, I rebuilt llvm-3.6 @3.6-r223943 and
clang-3.6 @3.6-r223943+analyzer with the following portfile
modification, without issue.

vq


diff --git a/dports/lang/llvm-3.6/Portfile b/dports/lang/llvm-3.6/Portfile
index a0b587e..24d464a 100644
--- a/dports/lang/llvm-3.6/Portfile
+++ b/dports/lang/llvm-3.6/Portfile
@@ -197,6 +197,9 @@ platform darwin {
         # http://trac.macports.org/ticket/33987
         configure.args-append --with-optimize-option=-Os
         configure.optflags    -Os
+    } else {
+        configure.optflags -O3 -march=native
+        configure.args-append --with-optimize-option='${configure.optflags}'
     }
 
     # TODO: The llvm build system sets a 10.1 deployment target on Yosemite