[poky] A problem of siteconfig mismatch

[Lu, Lianhao]

Hi guys,

We recently found a bug #892(http://bugzilla.pokylinux.org/show_bug.cgi?id=892) of the siteconfig mismatch problem in meta-environment package. The site config file is used by autoconf during cross compiling to provide default configuration values. 

In current poky, each package will use the function siteconfig_do_siteconfig_gencache() in siteconfig.bbclass to populate its own siteconfig file suitable for cross compiling into SITECONFIG_SYSROOTCACHE. And the function siteinfo_get_files() in siteinfo.bbclass will dump content of all the siteconfig files from SITECONFIG_SYSROOTCACHE into the final siteconfig file which will be used by the host autoconf during cross compilation. 

This requires all the siteconfig files must be available in SITECONFIG_SYSROOTCACHE when siteinfo_get_files() is being called. That's the reason for bug #892.

Since we now allow the user to specify the sysroot during cross compile, I think the siteconfig file should be consistent with the target sysroot, not with the SITECONFIG_SYSROOTCACHE. Otherwise there might be problems.

Any comment?

Best Regards,
-Lianhao Lu