[oe] [RFC] cmake cross-compilation paths

[Valentin Longchamp]

Hello,

I am trying to build cmake based programs that use QT with Openembedded. 
The actual support for cmake in OE worked until now that I only had 
"simple" dependencies. Now with QT as as dependency, I use the cmake 
FindQt4 Module that strongly relies on qmake to find the different QT 
cmake variables (try to run ${STAGINGBINDIR}/qmake4 -query).

The problem is that FindQt4 does not find the qmake4 (as I have proposed 
to rename it like that in my patch from yesterday) since the 
CMAKE_FIND_ROOT_PATH given to the cmake cmd in the classes/cmake.bbclass 
only is set to

-DCMAKE_FIND_ROOT_PATH=${STAGING_DIR_HOST}

that does not include ${STAGING_BIN_DIR}. Setting it to

-DCMAKE_FIND_ROOT_PATH=${STAGING_DIR}

makes configure fail (it cannot find the needed header files); and with

-DCMAKE_FIND_ROOT_PATH="${STAGING_DIR_HOST};${STAGING_DIR}"

qmake4 is not found either.

So if someone who knows cmake better than me can tell me how to give two 
paths to a cmd -DPATH_NAME=VALUE1 VALUE2 for cmake (and what would be 
the equivalent to STAGING_DIR_HOST for ${STAGING_DIR}/i686-linux in my 
case) that would help a lot (I am not sure it can be achieved).

All the inputs are greatly appreciated and if you could help me for the 
OE var names (especially for the equivalent to ${STAGING_DIR_HOST} that 
would point to ${STAGING_DIR}/i686-linux, that would already be a good 
start)

Thanks a lot

-- 
Valentin Longchamp, PhD Student, EPFL-STI-LSRO1
valentin.longchamp at epfl.ch, Phone: +41216937827
http://people.epfl.ch/valentin.longchamp
MEA3485, Station 9, CH-1015 Lausanne