Remove deprecated WITH_HOST_DALVIK.

Bug: 13751317
Fix the Mac build:
 - disable x86 selector removal that causes OS/X 10.9 kernel panics,
 - madvise don't need does zero memory on the Mac, factor into MemMap
   routine,
 - switch to the elf.h in elfutils to avoid Linux kernel dependencies,
 - we can't rely on exclusive_owner_ being available from other pthread
   libraries so maintain our own when futexes aren't available (we
   can't rely on the OS/X 10.8 hack any more),
 - fix symbol naming in assembly code,
 - work around C library differences,
 - disable backtrace in DumpNativeStack to avoid a broken libbacktrace
   dependency,
 - disable main thread signal handling logic,
 - align the stack in stub_test,
 - use $(HOST_SHLIB_SUFFIX) rather than .so in host make file variables.

Not all host tests are passing on the Mac with this change. dex2oat
works as does running HelloWorld.
Change-Id: I5a232aedfb2028524d49daa6397a8e60f3ee40d3
diff --git a/runtime/runtime.cc b/runtime/runtime.cc
index 89058c8..bcb4eb3 100644
--- a/runtime/runtime.cc
+++ b/runtime/runtime.cc
@@ -18,7 +18,9 @@
 
 // sys/mount.h has to come before linux/fs.h due to redefinition of MS_RDONLY, MS_BIND, etc
 #include <sys/mount.h>
+#ifdef __linux__
 #include <linux/fs.h>
+#endif
 
 #include <signal.h>
 #include <sys/syscall.h>
@@ -437,6 +439,7 @@
 
 // Do zygote-mode-only initialization.
 bool Runtime::InitZygote() {
+#ifdef __linux__
   // zygote goes into its own process group
   setpgid(0, 0);
 
@@ -467,6 +470,10 @@
   }
 
   return true;
+#else
+  UNIMPLEMENTED(FATAL);
+  return false;
+#endif
 }
 
 void Runtime::DidForkFromZygote() {