The problem is that libunwind fails to link in one configure test with error libunwind.so: undefined reference to `__aeabi_unwind_cpp_pr0'. The versions involved here are sys-libs/libunwind-1.1 and dev-util/ltrace-0.7.3. Fragment of config.log: configure:11991: checking libunwind.h usability configure:11991: armv7a-hardfloat-linux-gnueabi-gcc -c -O2 -pipe -mcpu=cortex-a7 -mfloat-abi=hard -mfpu=neon-vfpv4 -funsafe-math-optimizations -mthumb -mthumb-interwork -ggdb conftest.c >&5 configure:11991: $? = 0 configure:11991: result: yes configure:11991: checking libunwind.h presence configure:11991: armv7a-hardfloat-linux-gnueabi-gcc -E conftest.c configure:11991: $? = 0 configure:11991: result: yes configure:11991: checking for libunwind.h configure:11991: result: yes configure:12003: checking libunwind-ptrace.h usability configure:12003: armv7a-hardfloat-linux-gnueabi-gcc -c -O2 -pipe -mcpu=cortex-a7 -mfloat-abi=hard -mfpu=neon-vfpv4 -funsafe-math-optimizations -mthumb -mthumb-interwork -ggdb conftest.c >&5 configure:12003: $? = 0 configure:12003: result: yes configure:12003: checking libunwind-ptrace.h presence configure:12003: armv7a-hardfloat-linux-gnueabi-gcc -E conftest.c configure:12003: $? = 0 configure:12003: result: yes configure:12003: checking for libunwind-ptrace.h configure:12003: result: yes configure:12015: checking whether to use libunwind support configure:12031: result: yes configure:12046: checking for backtrace in -lunwind configure:12071: armv7a-hardfloat-linux-gnueabi-gcc -o conftest -O2 -pipe -mcpu=cortex-a7 -mfloat-abi=hard -mfpu=neon-vfpv4 -funsafe-math-optimizations -mthumb -mthumb-interwork -ggdb -Wl,-O1 -Wl,--as-needed conftest.c -lunwind -lelf >&5 /usr/lib/gcc/armv7a-hardfloat-linux-gnueabi/4.7.3/../../../libunwind.so: undefined reference to `__aeabi_unwind_cpp_pr0' /usr/lib/gcc/armv7a-hardfloat-linux-gnueabi/4.7.3/../../../libunwind.so: undefined reference to `__aeabi_unwind_cpp_pr1' collect2: error: ld returned 1 exit status configure:12071: $? = 1 configure: failed program was: | /* confdefs.h */ | #define PACKAGE_NAME "ltrace" | #define PACKAGE_TARNAME "ltrace" | #define PACKAGE_VERSION "0.7.3" | #define PACKAGE_STRING "ltrace 0.7.3" | #define PACKAGE_BUGREPORT "ltrace-devel@lists.alioth.debian.org" | #define PACKAGE_URL "" | #define STDC_HEADERS 1 | #define HAVE_SYS_TYPES_H 1 | #define HAVE_SYS_STAT_H 1 | #define HAVE_STDLIB_H 1 | #define HAVE_STRING_H 1 | #define HAVE_MEMORY_H 1 | #define HAVE_STRINGS_H 1 | #define HAVE_INTTYPES_H 1 | #define HAVE_STDINT_H 1 | #define HAVE_UNISTD_H 1 | #define HAVE_DLFCN_H 1 | #define LT_OBJDIR ".libs/" | #define PACKAGE "ltrace" | #define VERSION "0.7.3" | #define HAVE_ELF_H 1 | #define HAVE_GELF_H 1 | #define HAVE_LIBELF 1 | #define HAVE_LIBIBERTY 1 | #define HAVE_LIBSUPC__ 1 | #define HAVE_LIBSTDC__ 1 | #define HAVE_LIBUNWIND_H 1 | #define HAVE_LIBUNWIND_PTRACE_H 1 | /* end confdefs.h. */ | | /* Override any GCC internal prototype to avoid an error. | Use char because int might match the return type of a GCC | builtin and then its argument prototype would still apply. */ | #ifdef __cplusplus | extern "C" | #endif | char backtrace (); | int | main () | { | return backtrace (); | ; | return 0; | } configure:12080: result: no configure:12085: error: Couldn't find or use libunwind. I have found the same problem discussed there (http://lists.nongnu.org/archive/html/libunwind-devel/2010-08/msg00006.html). Reproducible: Always Steps to Reproduce: 1. Enable use flag unwind for ltrace 2. Emerge ltrace Actual Results: libunwind emerges ok, but ltrace fails in the configure step Expected Results: ltrace emerges ok emerge --info Portage 2.2.7 (default/linux/arm/13.0/armv7a, gcc-4.7.3, glibc-2.17, 3.4.79-cubietruck-02241-g9d1a44b armv7l) ================================================================= System uname: Linux-3.4.79-cubietruck-02241-g9d1a44b-armv7l-ARMv7_Processor_rev_4_-v7l-with-gentoo-2.2 KiB Mem: 2017248 total, 64960 free KiB Swap: 2097148 total, 2097036 free Timestamp of tree: Tue, 18 Feb 2014 10:15:01 +0000 ld GNU ld (GNU Binutils) 2.23.2 app-shells/bash: 4.2_p45 dev-lang/python: 2.7.5-r3, 3.2.5-r3, 3.3.3 dev-util/cmake: 2.8.11.2 dev-util/pkgconfig: 0.28 sys-apps/baselayout: 2.2 sys-apps/openrc: 0.12.4 sys-apps/sandbox: 2.6-r1 sys-devel/autoconf: 2.69 sys-devel/automake: 1.11.6, 1.12.6, 1.13.4 sys-devel/binutils: 2.23.2 sys-devel/gcc: 4.6.3, 4.7.3-r1 sys-devel/gcc-config: 1.7.3 sys-devel/libtool: 2.4.2 sys-devel/make: 3.82-r4 sys-kernel/linux-headers: 3.9 (virtual/os-headers) sys-libs/glibc: 2.17 Repositories: gentoo location: /usr/portage sync-type: rsync sync-uri: rsync://rsync.europe.gentoo.org/gentoo-portage priority: -1000 x-portage location: /usr/local/portage masters: gentoo priority: 0 ACCEPT_KEYWORDS="arm" ACCEPT_LICENSE="* -@EULA" ACCEPT_PROPERTIES="*" ACCEPT_RESTRICT="*" ARCH="arm" AUTOCLEAN="yes" BOOTSTRAP_USE="cxx unicode python_targets_python3_3 python_targets_python2_7" CBUILD="armv7a-hardfloat-linux-gnueabi" CFLAGS="-O2 -pipe -mcpu=cortex-a7 -mfloat-abi=hard -mfpu=neon-vfpv4 -funsafe-math-optimizations -mthumb -mthumb-interwork -ggdb" CHOST="armv7a-hardfloat-linux-gnueabi" CLEAN_DELAY="5" COLLISION_IGNORE="/lib/modules/* *.py[co] *$py.class */dropin.cache" CONFIG_PROTECT="/etc /usr/share/gnupg/qualified.txt /var/spool/munin-async/.ssh" CONFIG_PROTECT_MASK="/etc/ca-certificates.conf /etc/env.d /etc/fonts/fonts.conf /etc/gconf /etc/gentoo-release /etc/php/apache2-php5.5/ext-active/ /etc/php/cgi-php5.5/ext-active/ /etc/php/cli-php5.5/ext-active/ /etc/revdep-rebuild /etc/sandbox.d /etc/terminfo" CXXFLAGS="-O2 -pipe -mcpu=cortex-a7 -mfloat-abi=hard -mfpu=neon-vfpv4 -funsafe-math-optimizations -mthumb -mthumb-interwork -ggdb" DISTDIR="/usr/portage/distfiles" EDITOR="/usr/bin/vim" ELIBC="glibc" EMERGE_DEFAULT_OPTS="--jobs=2 --load-average=2.5 --verbose" EMERGE_WARNING_DELAY="10" EPREFIX="" EROOT="/" FCFLAGS="-O2 -pipe -march=armv7-a" FEATURES="assume-digests binpkg-logs config-protect-if-modified distlocks ebuild-locks fixlafiles merge-sync news parallel-fetch preserve-libs protect-owned sandbox sfperms splitdebug strict unknown-features-warn unmerge-logs unmerge-orphans userfetch userpriv usersandbox usersync" FFLAGS="-O2 -pipe -march=armv7-a" GCC_SPECS="" GENTOO_MIRRORS="http://mirror.ovh.net/gentoo-distfiles/ http://mirror.cambrium.nl/pub/os/linux/gentoo/ http://ftp.dei.uc.pt/pub/linux/gentoo/" GRUB_PLATFORMS="" HOME="/root" INFOPATH="/usr/share/info:/usr/share/gcc-data/armv7a-hardfloat-linux-gnueabi/4.7.3/info:/usr/share/binutils-data/armv7a-hardfloat-linux-gnueabi/2.23.2/info" INPUT_DEVICES="keyboard mouse evdev" IUSE_IMPLICIT="prefix" KERNEL="linux" LANG="es_ES.UTF-8" LC_MESSAGES="C" LDFLAGS="-Wl,-O1 -Wl,--as-needed" LESS="-R -M --shift 5" LESSOPEN="|lesspipe %s" LINGUAS="es_ES es en en_US" LOGNAME="root" MAIL="/var/mail/root" MAKEOPTS="-j2" MANPATH="/usr/local/share/man:/usr/share/man:/usr/share/gcc-data/armv7a-hardfloat-linux-gnueabi/4.7.3/man:/usr/share/binutils-data/armv7a-hardfloat-linux-gnueabi/2.23.2/man:/usr/lib/php5.5/man/" MULTIOSDIRS="." PAGER="/usr/bin/less" PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/opt/bin:/usr/armv7a-hardfloat-linux-gnueabi/gcc-bin/4.7.3:/usr/armv7a-hardfloat-linux-gnueabi/avr/gcc-bin/4.7.3" PKGDIR="/usr/portage/packages" PORTAGE_ARCHLIST="ppc-macos sparc x64-macos x64-freebsd m68k x64-openbsd x86-macos sparc64-freebsd ia64-linux amd64-linux ia64-hpux x86-winnt s390 x86 x86-freebsd amd64 x86-solaris ppc-openbsd sh ppc64-linux m68k-mint arm ia64 x86-fbsd amd64-fbsd arm64 x86-interix ppc x86-openbsd sparc-fbsd sparc64-solaris mips sparc-solaris hppa x64-solaris x86-linux arm-linux x86-cygwin alpha ppc-aix ppc64 hppa-hpux x86-netbsd" PORTAGE_BIN_PATH="/usr/lib/portage/bin" PORTAGE_COMPRESS_EXCLUDE_SUFFIXES="css gif htm[l]? jp[e]?g js pdf png" PORTAGE_CONFIGROOT="/" PORTAGE_DEBUG="0" PORTAGE_DEPCACHEDIR="/var/cache/edb/dep" PORTAGE_FETCH_CHECKSUM_TRY_MIRRORS="5" PORTAGE_FETCH_RESUME_MIN_SIZE="350K" PORTAGE_GID="250" PORTAGE_GPG_SIGNING_COMMAND="gpg --sign --digest-algo SHA256 --clearsign --yes --default-key "${PORTAGE_GPG_KEY}" --homedir "${PORTAGE_GPG_DIR}" "${FILE}"" PORTAGE_INST_GID="0" PORTAGE_INST_UID="0" PORTAGE_INTERNAL_CALLER="1" PORTAGE_NICENESS="3" PORTAGE_OVERRIDE_EPREFIX="" PORTAGE_PYM_PATH="/usr/lib/portage/pym" PORTAGE_PYTHONPATH="/usr/lib/portage/pym" PORTAGE_REPOSITORIES="[DEFAULT] main-repo = gentoo [gentoo] location = /usr/portage masters = priority = -1000 sync-type = rsync sync-uri = rsync://rsync.europe.gentoo.org/gentoo-portage [x-portage] location = /usr/local/portage masters = gentoo priority = 0 " PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --omit-dir-times --compress --force --whole-file --delete --stats --human-readable --timeout=180 --exclude=/distfiles --exclude=/local --exclude=/packages" PORTAGE_RSYNC_RETRIES="-1" PORTAGE_SYNC_STALE="30" PORTAGE_TMPDIR="/var/tmp" PORTAGE_VERBOSE="1" PORTAGE_WORKDIR_MODE="0700" PORTAGE_XATTR_EXCLUDE="security.* system.nfs4_acl" PORTDIR="/usr/portage" PORTDIR_OVERLAY="/usr/local/portage" PORT_LOGDIR_CLEAN="find "${PORT_LOGDIR}" -type f ! -name "summary.log*" -mtime +7 -delete" PROFILE_ONLY_VARIABLES="ARCH ELIBC IUSE_IMPLICIT KERNEL USERLAND USE_EXPAND_IMPLICIT USE_EXPAND_UNPREFIXED USE_EXPAND_VALUES_ARCH USE_EXPAND_VALUES_ELIBC USE_EXPAND_VALUES_KERNEL USE_EXPAND_VALUES_USERLAND" PWD="/root" PYTHONDONTWRITEBYTECODE="1" PYTHON_SINGLE_TARGET="python2_7" PYTHON_TARGETS="python2_7 python3_3" ROOT="/" ROOTPATH="/opt/bin:/usr/armv7a-hardfloat-linux-gnueabi/gcc-bin/4.7.3:/usr/armv7a-hardfloat-linux-gnueabi/avr/gcc-bin/4.7.3" RPMDIR="/usr/portage/rpm" RUBY_TARGETS="ruby19 ruby18" SHELL="/bin/bash" SHLVL="1" SSH_TTY="/dev/pts/0" SYNC="rsync://rsync.europe.gentoo.org/gentoo-portage" TERM="xterm" UNINSTALL_IGNORE="/lib/modules/*" USE="acl apache apache2 arm avahi berkdb bzip2 cli cracklib crypt cxx dbus dri fam fortran gd gdbm iconv ipv6 jpeg ldap modules ncurses nls nptl openmp pam pcre perl png readline session ssl tcpd threads truetype unicode zlib" ELIBC="glibc" INPUT_DEVICES="keyboard mouse evdev" KERNEL="linux" LINGUAS="es_ES es en en_US" PHP_TARGETS="php5-5" PYTHON_SINGLE_TARGET="python2_7" PYTHON_TARGETS="python2_7 python3_3" RUBY_TARGETS="ruby19 ruby18" USERLAND="GNU" VIDEO_CARDS="exynos fbdev omap omapfb dummy v4l" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account" USER="root" USERLAND="GNU" USE_EXPAND="ABI_MIPS ABI_X86 ALSA_CARDS APACHE2_MODULES APACHE2_MPMS CALLIGRA_FEATURES CAMERAS COLLECTD_PLUGINS CROSSCOMPILE_OPTS CURL_SSL DRACUT_MODULES DVB_CARDS ELIBC ENLIGHTENMENT_MODULES FCDSL_CARDS FFTOOLS FOO2ZJS_DEVICES FRITZCAPI_CARDS GPSD_PROTOCOLS GRUB_PLATFORMS INPUT_DEVICES KERNEL LCD_DEVICES LIBREOFFICE_EXTENSIONS LINGUAS LIRC_DEVICES MONKEYD_PLUGINS NETBEANS_MODULES NGINX_MODULES_HTTP NGINX_MODULES_MAIL OFED_DRIVERS OFFICE_IMPLEMENTATION OPENMPI_FABRICS OPENMPI_OFED_FEATURES OPENMPI_RM PHP_TARGETS PYTHON_SINGLE_TARGET PYTHON_TARGETS QEMU_SOFTMMU_TARGETS QEMU_USER_TARGETS RUBY_TARGETS SANE_BACKENDS USERLAND UWSGI_PLUGINS VIDEO_CARDS VOICEMAIL_STORAGE XFCE_PLUGINS XTABLES_ADDONS" USE_EXPAND_HIDDEN="ABI_MIPS ABI_X86 CROSSCOMPILE_OPTS ELIBC KERNEL USERLAND" USE_EXPAND_IMPLICIT="ARCH ELIBC KERNEL USERLAND" USE_EXPAND_UNPREFIXED="ARCH" USE_EXPAND_VALUES_ARCH="alpha amd64 amd64-fbsd amd64-linux arm arm-linux arm64 hppa hppa-hpux ia64 ia64-hpux ia64-linux m68k m68k-mint mips ppc ppc64 ppc64-linux ppc-aix ppc-macos ppc-openbsd s390 sh sparc sparc64-freebsd sparc64-solaris sparc-fbsd sparc-solaris x64-freebsd x64-macos x64-openbsd x64-solaris x86 x86-cygwin x86-fbsd x86-freebsd x86-interix x86-linux x86-macos x86-netbsd x86-openbsd x86-solaris x86-winnt" USE_EXPAND_VALUES_ELIBC="AIX Cygwin Darwin FreeBSD glibc HPUX Interix mintlib musl NetBSD OpenBSD SunOS uclibc Winnt" USE_EXPAND_VALUES_KERNEL="AIX Cygwin Darwin FreeBSD freemint HPUX Interix linux NetBSD OpenBSD SunOS Winnt" USE_EXPAND_VALUES_USERLAND="BSD GNU" USE_ORDER="env:pkg:conf:defaults:pkginternal:repo:env.d" VIDEO_CARDS="exynos fbdev omap omapfb dummy v4l" XTABLES_ADDONS="quota2 psd pknock lscan length2 ipv4options ipset ipp2p iface geoip fuzzy condition tee tarpit sysrq steal rawnat logmark ipmark dhcpmac delude chaos account" _="/usr/bin/emerge"
You might want to try again with dev-util/ltrace-0.7.3_p4 which applies Debian's patches, including a 05-sparc-ftbfs patch.
Same result: configure:12055: checking for backtrace in -lunwind configure:12080: armv7a-hardfloat-linux-gnueabi-gcc -o conftest -O2 -pipe -mcpu=cortex-a7 -mfloat-abi =hard -mfpu=neon-vfpv4 -funsafe-math-optimizations -mthumb -mthumb-interwork -ggdb -Wl,-O1 -Wl,--as- needed conftest.c -lunwind -lelf >&5 /usr/lib/gcc/armv7a-hardfloat-linux-gnueabi/4.7.3/../../../libunwind.so: undefined reference to `__ae abi_unwind_cpp_pr0' /usr/lib/gcc/armv7a-hardfloat-linux-gnueabi/4.7.3/../../../libunwind.so: undefined reference to `__ae abi_unwind_cpp_pr1' collect2: error: ld returned 1 exit status configure:12080: $? = 1 configure: failed program was: | /* confdefs.h */ | #define PACKAGE_NAME "ltrace" | #define PACKAGE_TARNAME "ltrace" | #define PACKAGE_VERSION "0.7.3" | #define PACKAGE_STRING "ltrace 0.7.3" | #define PACKAGE_BUGREPORT "ltrace-devel@lists.alioth.debian.org" | #define PACKAGE_URL "" | #define STDC_HEADERS 1 | #define HAVE_SYS_TYPES_H 1 | #define HAVE_SYS_STAT_H 1 | #define HAVE_STDLIB_H 1 | #define HAVE_STRING_H 1 | #define HAVE_MEMORY_H 1 | #define HAVE_STRINGS_H 1 | #define HAVE_INTTYPES_H 1 | #define HAVE_STDINT_H 1 | #define HAVE_UNISTD_H 1 | #define HAVE_DLFCN_H 1 | #define LT_OBJDIR ".libs/" | #define PACKAGE "ltrace" | #define VERSION "0.7.3" | #define HAVE_ELF_H 1 | #define HAVE_GELF_H 1 | #define HAVE_LIBELF 1 | #define HAVE_LIBIBERTY 1 | #define HAVE_LIBSUPC__ 1 | #define HAVE_LIBSTDC__ 1 | #define HAVE_LIBUNWIND_H 1 | #define HAVE_LIBUNWIND_PTRACE_H 1 | /* end confdefs.h. */ | | /* Override any GCC internal prototype to avoid an error. | Use char because int might match the return type of a GCC | builtin and then its argument prototype would still apply. */ | #ifdef __cplusplus | extern "C" | #endif | char backtrace (); | #define PACKAGE_URL "" | #define STDC_HEADERS 1 | #define HAVE_SYS_TYPES_H 1 | #define HAVE_SYS_STAT_H 1 | #define HAVE_STDLIB_H 1 | #define HAVE_STRING_H 1 | #define HAVE_MEMORY_H 1 | #define HAVE_STRINGS_H 1 | #define HAVE_INTTYPES_H 1 | #define HAVE_STDINT_H 1 | #define HAVE_UNISTD_H 1 | #define HAVE_DLFCN_H 1 | #define LT_OBJDIR ".libs/" | #define PACKAGE "ltrace" | #define VERSION "0.7.3" | #define HAVE_ELF_H 1 | #define HAVE_GELF_H 1 | #define HAVE_LIBELF 1 | #define HAVE_LIBIBERTY 1 | #define HAVE_LIBSUPC__ 1 | #define HAVE_LIBSTDC__ 1 | #define HAVE_LIBUNWIND_H 1 | #define HAVE_LIBUNWIND_PTRACE_H 1 | /* end confdefs.h. */ | | /* Override any GCC internal prototype to avoid an error. | Use char because int might match the return type of a GCC | builtin and then its argument prototype would still apply. */ | #ifdef __cplusplus | extern "C" | #endif | char backtrace (); | int | main () | { | return backtrace (); | ; | return 0; | } configure:12089: result: no configure:12094: error: Couldn't find or use libunwind. | int | main () | { | return backtrace (); | ; | return 0; | } configure:12089: result: no configure:12094: error: Couldn't find or use libunwind. But I have tested and it's related to --as-needed, I can compile the test program if I take out the -Wl,--as-needed flag: cubietruck ltrace-0.7.3 # armv7a-hardfloat-linux-gnueabi-gcc -o conftest -O2 -pipe -mcpu=cortex-a7 -mfloat-abi=hard -mfpu=neon-vfpv4 -funsafe-math-optimizations -mthumb -mthumb-interwork -ggdb -Wl,-O1 -Wl,--as-needed conftest.c -lunwind -lelf /usr/lib/gcc/armv7a-hardfloat-linux-gnueabi/4.7.3/../../../libunwind.so: undefined reference to `__aeabi_unwind_cpp_pr0' /usr/lib/gcc/armv7a-hardfloat-linux-gnueabi/4.7.3/../../../libunwind.so: undefined reference to `__aeabi_unwind_cpp_pr1' collect2: error: ld returned 1 exit status cubietruck ltrace-0.7.3 # armv7a-hardfloat-linux-gnueabi-gcc -o conftest -O2 -pipe -mcpu=cortex-a7 -mfloat-abi=hard -mfpu=neon-vfpv4 -funsafe-math-optimizations -mthumb -mthumb-interwork -ggdb -Wl,-O1 conftest.c -lunwind -lelf cubietruck ltrace-0.7.3 #
(In reply to Jeroen Roovers from comment #1) > Debian's patches, including a 05-sparc-ftbfs patch. I may have confused the architecture there.
It looks like old gcc's underlinking issue, works fine here on gcc-5.3.0. Please reopen if it breaks on newer gcc for you.
