ARM support, with some build system changes to support x86-64, arm, and i386 in an autoconf style build in Linux. The O2 build for the unit tests is still broken but I'm checking this in to unblock people

A=nealsid
R=ajwong, hannahtang, ted.mielczarek



git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@541 4c0a9323-5329-0410-9bdc-e9ce6186880e

configure.ac

@@ -46,6 +46,26 @@ AC_PROG_LIBTOOL
 AC_SUBST(LIBTOOL_DEPS)
 
 AC_HEADER_STDC
+m4_include(m4/ax_pthread.m4)
+AX_PTHREAD
+
+AC_ARG_ENABLE(m32,
+              AS_HELP_STRING([--enable-m32],
+                             [Compile/build with -m32]
+                             [(default is no)]),
+              [case "${enableval}" in
+                 yes)
+		   CFLAGS=$(CFLAGS) -m32
+                   usem32=true
+                   ;;
+                 no)
+                   usem32=false
+                   ;;
+                 *)
+                   AC_MSG_ERROR(bad value ${enableval} for --enable-m32)
+                   ;;
+               esac],
+              [usem32=false])
 
 AC_ARG_ENABLE(selftest,
               AS_HELP_STRING([--enable-selftest],