klibc fails to cross-build
The build command is:
xdeb --only-explicit -a armel --prefer-apt --apt-source --debug --force-rebuild klibc
The actual build command xdeb issues is:
debuild --no-lintian -eUSER -eCONFIG_SITE=/etc/dpkg-cross/cross-config.armel -eDEB_BUILD_OPTIONS=nocheck -eGTEST_INCLUDEDIR=/usr/arm-linux-gnueabi/include -eGTEST_LIBDIR=/usr/arm-linux-gnueabi/lib -ePKG_CONFIG_LIBDIR=/usr/arm-linux-gnueabi/lib/pkgconfig:/usr/arm-linux-gnueabi/share/pkgconfig:/usr/share/pkgconfig -eDH_VERBOSE=1 -aarmel -b -uc -us -tc
To easily reproduce the build environment in which this bug was discovered follow the HOWTO here:
https://wiki.linaro.org/Platform/DevPlatform/CrossCompile/CrossBuildNano
It tries to build for the Build arch and thus falls over when it can't find headers
gcc -Wp,-MD,usr/klibc/.vsnprintf.o.d -nostdinc -iwithprefix include -I/home/wookey/testing/build/build/xdeb/klibc/usr/include/arch/x86_64 -Iusr/include/arch/x86_64 -I/home/wookey/testing/build/build/xdeb/klibc/usr/include/bits64 -Iusr/include/bits64 -I/home/wookey/testing/build/build/xdeb/klibc/usr/klibc/../include -Iusr/klibc/../include -I/home/wookey/testing/build/build/xdeb/klibc/usr/include -Iusr/include -I/home/wookey/testing/build/build/xdeb/klibc/linux/include -Ilinux/include -I/home/wookey/testing/build/build/xdeb/klibc/linux/arch/x86/include -Ilinux/arch/x86/include -D__KLIBC__=1 -D__KLIBC_MINOR__=5 -D_BITSIZE=64 -fno-stack-protector -fwrapv -m64 -Os -fno-asynchronous-unwind-tables -fomit-frame-pointer -falign-functions=1 -falign-jumps=1 -falign-loops=1 -W -Wall -Wno-sign-compare -Wno-unused-parameter -c -o usr/klibc/vsnprintf.o usr/klibc/vsnprintf.c
In file included from /home/wookey/testing/build/build/xdeb/klibc/usr/klibc/../include/sys/types.h:15:0,
from /home/wookey/testing/build/build/xdeb/klibc/usr/klibc/../include/unistd.h:11,
from /home/wookey/testing/build/build/xdeb/klibc/usr/klibc/../include/stdio.h:11,
from usr/klibc/vsnprintf.c:13:
/home/wookey/testing/build/build/xdeb/klibc/linux/include/linux/posix_types.h:47:29: fatal error: asm/posix_types.h: No such file or directory
Marcin seems to have cleaned this up in bug 963047 (looks like a slightly different failure, but it should still resolve the fundamental problem of making it cross-build).