execinfo.h isn't needed on Mac OS X for Host.mm.

Summary: This is no longer needed as this file no longer calls backtrace().

Reviewers: clayborg

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D13049

llvm-svn: 248457

lldb/source/Host/macosx/Host.mm

@@ -25,7 +25,6 @@
 
 #include <asl.h>
 #include <crt_externs.h>
-#include <execinfo.h>
 #include <grp.h>
 #include <libproc.h>
 #include <pwd.h>