[oe] Cross compiling for x86_64-mingw32

[Francois Retief]

Hallo,

For an upcomming project we need to build a x86_64-mingw32 SDK.   So I
started
down the road to create such an SDK. I am using [1] as reference to build
OE packages.

So far I gathered that I need to create a sdk conf file for this target:

# cat ${OECORE}/meta/conf/machine_sdk/x86_64-mingw32.conf
SDK_ARCH=x86_64
SDK_OS=mingw32

Then the next steps is to make sure I can build binutils:

# SDKMACHINE=x86_64-mingw32 bitbake binutils-crosssdk

This works. The next step is to build the gcc-initial:

# SDKMACHINE=x86_64-mingw32 bitbake gcc-crosssdk-initial

But this step requires the mingw-w64 headers. Using references to recipies
from
the old oe-classic tree, I was able to craft a recipe for the
mingw-w64-headers.

recipes-devtools/mingw/mingw-w64-headers_2.0.8.bb
-----------------------------------------------------------
DESCRIPTION = "Header files from the MingGW-w64 project"
LICENSE = "ZPL"
LIC_FILES_CHKSUM = "file://../COPYING;md5=3194ff3a0d16f018784d1847bc6a3c4d"

PR = "r1"

BBCLASSEXTEND = "nativesdk"

DEFAULT_PREFERENCE = "-1"
DEFAULT_PREFERENCE_mingw32 = "1"

SRC_URI =
"${SOURCEFORGE_MIRROR}/project/mingw-w64/mingw-w64/mingw-w64-release/mingw-w64-v${PV}.tar.gz"
SRC_URI[md5sum] = "659e5baf45ac8e8b8526f29786ee1112"
SRC_URI[sha256sum] =
"1a5a2c57f90c7f1b5eb8402a52f93de645925a8af62c2cfe748f39ce66008cf4"

S = "${WORKDIR}/mingw-w64-v${PV}/mingw-w64-headers"
B = "${WORKDIR}/build-${TARGET_SYS}"

inherit autotools

INHIBIT_DEFAULT_DEPS = "1"
DEPENDS = ""

do_configure() {
    oe_runconf
}

do_compile() {
    :
}
-----------------------------------------------------------

My question is how do one get the resulting header fiels in the right place
so that
gcc-crosssdk-initial can pick it up. From the error messages I can see that
GCC is looking in
${TMPDIR}/sysroots/x86_64-nativesdk-angstromsdk-mingw32/usr/local/oecore-x86_64/sysroots/x86_64-angstromsdk-mingw32/usr/include

What is missing from the recipe?  When I run the recipe, it builds fine,
but the sysroot folder is still empty.

# SDKMACHINE=x86_64-mingw32 bitbake nativesdk-mingw-w64-headers

Any suggestions is helpful.

Cheers
  Francois

[1] http://www.nathancoulson.com/proj_cross.php