var/tmp/portage/sys-libs/glibc-2.7/work/build-x86-x86_64-pc-linux-gnu-nptl/libc_pic.os: In function `_nscd_get_map_ref': var/tmp/portage/sys-libs/glibc-2.7/work/build-x86-x86_64-pc-linux-gnu-nptl/libc_pic.os:nscd_gethst_r.c:(.text+0xde9c4): more undefined references to `_sync_fetch_and_add_4' follow

Nscd_gethst_r.c:(.text+0xde97d): undefined reference to `_sync_fetch_and_add_4' var/tmp/portage/sys-libs/glibc-2.7/work/build-x86-x86_64-pc-linux-gnu-nptl/libc_pic.os: In function `nscd_gethst_r': Nscd_getgr_r.c:(.text+0xde310): undefined reference to `_sync_fetch_and_add_4' Nscd_getgr_r.c:(.text+0xde2cb): undefined reference to `_sync_fetch_and_add_4' var/tmp/portage/sys-libs/glibc-2.7/work/build-x86-x86_64-pc-linux-gnu-nptl/libc_pic.os: In function `nscd_getgr_r': Nscd_getpw_r.c:(.text+0xddecb): undefined reference to `_sync_fetch_and_add_4' Nscd_getpw_r.c:(.text+0xdde87): undefined reference to `_sync_fetch_and_add_4' var/tmp/portage/sys-libs/glibc-2.7/work/build-x86-x86_64-pc-linux-gnu-nptl/libc_pic.os: In function `nscd_getpw_r': (.text+0x7b8ef): undefined reference to `_sync_bool_compare_and_swap_4' var/tmp/portage/sys-libs/glibc-2.7/work/build-x86-x86_64-pc-linux-gnu-nptl/libc_pic.os: In function `_fork': I686-pc-linux-gnu-gcc -shared -static-libgcc -Wl,-O1 -Wl,-z,defs -Wl,-dynamic-linker=/lib32/ld-linux.so.2 -o /var/tmp/portage/sys-libs/glibc-2.7/work/build-x86-x86_64-pc-linux-gnu-nptl/libc.so -lgcc Something is definitely broken, but I have no idea what it is. I don't really understand what's causing these problems, or how that fixes it. There seems to be some sort of black magic going on here. I thought this might have something to do with the CFLAGS being passed to the GCC build process (-march, in particular), but it seems to have that trouble no matter what CFLAGS are used to build GCC.Ī workaround I am currently using is to add -march=i686 to the CFLAGS added by eselect-compiler when i686-pc-linux-gnu-gcc is called, in /etc/eselect/compiler/x86_64-pc-linux-gnu-4.2.2.conf this generates proper code in 32-bit mode. This manifests especially when building glibc (tested: sys-libs/glibc-2.7), as that uses a bunch of 32-bit code.

GCC 4.2 (tested: sys-devel/gcc-4.2.2) mistakenly inserts the 64-bit atomic builtins into 32-bit code that it generates, creating linker errors during 32-bit compilation when ld cannot find any references to _sync_bool_compare_and_swap_4, _sync_fetch_and_add_4, _sync_val_compare_and_swap_4, etc.

Intel c compiler __sync_fetch_and_add