It fails like this when building for abi_x86_32 on xfs with 64-bit inode numbers: /var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src-abi_x86_32.x86/Release/bin/clang -fPIC -I/var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src/projects/compiler-rt/lib -I/var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src/projects/compiler-rt/include -Wall -Werror -O3 -fomit-frame-pointer -m32 -c -o /var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src-abi_x86_32.x86/tools/clang/runtime/compiler-rt/clang_linux/profile-i386/i386/SubDir.lib__profile/GCDAProfiling.o /var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src/projects/compiler-rt/lib/profile/GCDAProfiling.c /var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src/projects/compiler-rt/lib/profile/GCDAProfiling.c:23:10: fatal error: 'errno.h' file not found #include <errno.h> ^ 1 error generated. Makefile:267: recipe for target '/var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src-abi_x86_32.x86/tools/clang/runtime/compiler-rt/clang_linux/profile-i386/i386/SubDir.lib__profile/GCDAProfiling.o' failed make[5]: *** [/var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src-abi_x86_32.x86/tools/clang/runtime/compiler-rt/clang_linux/profile-i386/i386/SubDir.lib__profile/GCDAProfiling.o] Error 1 make[5]: Leaving directory '/var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src/projects/compiler-rt' Makefile:164: recipe for target 'BuildRuntimeLibraries' failed make[4]: *** [BuildRuntimeLibraries] Error 2 make[4]: Leaving directory '/var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src-abi_x86_32.x86/tools/clang/runtime/compiler-rt' /var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src/Makefile.rules:932: recipe for target 'compiler-rt/.makeall' failed make[3]: *** [compiler-rt/.makeall] Error 2 make[3]: Leaving directory '/var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src-abi_x86_32.x86/tools/clang/runtime' /var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src/Makefile.rules:873: recipe for target 'all' failed make[2]: *** [all] Error 1 make[2]: Leaving directory '/var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src-abi_x86_32.x86/tools/clang' /var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src/Makefile.rules:932: recipe for target 'clang/.makeall' failed make[1]: *** [clang/.makeall] Error 2 make[1]: Leaving directory '/var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src-abi_x86_32.x86/tools' /var/tmp/portage/sys-devel/llvm-3.6.1/work/llvm-3.6.1.src/Makefile.rules:873: recipe for target 'all' failed make: *** [all] Error 1 The problem is solved by calling append-lfs-flags from flag-o-matic.eclass at the beginning of src_configure.
Thanks Zac, I added append-lfs-flags to both latest 3.6.1 and live ebuild