Add compiler version checks for what we want to support going forward,

and make us actually build with clang (the log_message_handler.cc change
and config.make change)

config.make

@@ -0,0 +1,7 @@
+if [ -n "$NGX_CLANG_VER" ]; then
+  # Chromium headers assume clang is always in C++11 mode. Oblige it.
+  for ps_src_file in $PS_NGX_SRCS; do
+    ps_obj_file="$NGX_OBJS/addon/src/`basename $ps_src_file .cc`.o"
+    echo "$ps_obj_file : CFLAGS += --std=c++11" >> $NGX_MAKEFILE
+  done
+fi