The attached patch changes the gcc-include type of "M-x compile" to be
INFO. Let's say I have 3 source files:

a.c:
#include "a.h"

a.h:
#include "b.h"

b.h:
asdf;


Clearly trying to compile a.c fails since b.h has an error. I do M-x
compile, and build with "gcc -c -o a.o a.c". I get a *compilation*
buffer with

 -*- mode: compilation; default-directory: "/tmp/" -*-
 Compilation started at Sat Jun 21 01:43:01

 gcc -c -o a.o a.c
 In file included from a.h:1:0,
                  from a.c:1:
 b.h:1:1: warning: data definition has no type or storage class [enabled by default]
  aadsf;
  ^

 Compilation finished at Sat Jun 21 01:43:01


Prior to this patch the line that contains "from a.h:1:0," was seen as
INFO and the line that contains "from a.c:1:" was seen as a
WARNING. This patch makes them both INFO.