The OE environment sets and exports CPP as being the target gcc. When building 
gcc-cross-canadian for a mingw targetted sdk, the following can be found in
build.x86_64-pokysdk-mingw32.i586-poky-linux/build-x86_64-linux/libiberty/config.log:

configure:3641: checking for _FILE_OFFSET_BITS value needed for large files
configure:3666: gcc  -c -isystem/media/build1/poky/build/tmp/sysroots/x86_64-linux/usr/include -O2 -pipe  conftest.c >&5
configure:3666: $? = 0
configure:3698: result: no
configure:3786: checking how to run the C preprocessor
configure:3856: result: x86_64-pokysdk-mingw32-gcc -E --sysroot=/media/build1/poky/build/tmp/sysroots/x86_64-nativesdk-mingw32-pokysdk-mingw32
configure:3876: x86_64-pokysdk-mingw32-gcc -E --sysroot=/media/build1/poky/build/tmp/sysroots/x86_64-nativesdk-mingw32-pokysdk-mingw32  conftest.c
configure:3876: $? = 0

Note this is a *build* target (in build-x86_64-linux) so it should be using 
the host "gcc", not x86_64-pokysdk-mingw32-gcc. Since the mingw32 headers are 
very different, using the wrong cpp is a real problem. It is leaking into 
configure through the CPP variable. Ultimately this leads to build failures 
related to not being able to include a process.h file for pem-unix.c.

The fix is to ensure we export a sane CPP value into the build environment when
using build targets. We could define a CPP_FOR_BUILD value which may be the version
which needs to be upstreamed but for now, this fix is good enough to avoid the 
problem.

RP 22/08/2013

Upstream-Status: Pending

Index: gcc-4.8.1/Makefile.in
===================================================================
--- gcc-4.8.1.orig/Makefile.in	2013-03-30 11:25:03.000000000 +0000
+++ gcc-4.8.1/Makefile.in	2013-08-13 12:03:17.151988882 +0000
@@ -149,6 +149,7 @@
 	AR="$(AR_FOR_BUILD)"; export AR; \
 	AS="$(AS_FOR_BUILD)"; export AS; \
 	CC="$(CC_FOR_BUILD)"; export CC; \
+	CPP="$(CC_FOR_BUILD) -E"; export CPP; \
 	CFLAGS="$(CFLAGS_FOR_BUILD)"; export CFLAGS; \
 	CONFIG_SHELL="$(SHELL)"; export CONFIG_SHELL; \
 	CXX="$(CXX_FOR_BUILD)"; export CXX; \