check for and enable Large File Support automatically

If you try to process a file using a 32bit build that is larger than
2GiB in size, the linux kernel will reject things:
$ strace -eopen dump_syms ./chrome ./ > chrome.sym
...
open(".//chrome.debug", O_RDONLY)       = -1 EOVERFLOW (Value too large for defined data type)

So let's use the existing autoconf macro to check for and enable support
as need be.

We have to shift the existing m32 logic up to before we start doing
feature test macros though otherwise a simple configure won't work:
$ ./configure --enable-m32
This is because it first tests LFS and such w/out the -m32 flags.

BUG=chromium:266064
TEST=`./configure --enable-m32 && make && make check` passes
R=benchan@chromium.org

Review URL: https://breakpad.appspot.com/619002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1250 4c0a9323-5329-0410-9bdc-e9ce6186880e
Use AM_MAINTAINER_MODE so configure supports --enable-maintainer-mode
A=mcgrathr
R=bradnelson at https://breakpad.appspot.com/864003

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1251 4c0a9323-5329-0410-9bdc-e9ce6186880e
autoreconf -f -i

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1252 4c0a9323-5329-0410-9bdc-e9ce6186880e
Conditionalize use of <cpuid.h> header

This header only exists for x86 environments, but was included
unconditionally.  That broke the builds for all non-x86 environments.

R=mark@chromium.org
BUG=

Review URL: https://breakpad.appspot.com/824003

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1253 4c0a9323-5329-0410-9bdc-e9ce6186880e
Address additional comments from r1248. Fix the register to check and fix some style nits.

BUG=495
R=mark@chromium.org

Review URL: https://breakpad.appspot.com/834003

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1254 4c0a9323-5329-0410-9bdc-e9ce6186880e