http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49992
--- Comment #41 from Jack Howarth <howarth at nitro dot med.uc.edu> 2011-08-11 13:22:46 UTC --- Note that I can also confirm the failure from Comment 4 on darwin11. Using unpatched gcc trunk svn at r177665 when building with clang on darwin11 using... ../gcc-4.7-20110811/configure --prefix=/sw --prefix=/sw/lib/gcc4.7 --mandir=/sw/share/man --infodir=/sw/lib/gcc4.7/info --enable-languages=c,c++,fortran,objc,obj-c++,java --with-gmp=/sw --with-libiconv-prefix=/sw --with-ppl=/sw --with-cloog=/sw --with-mpc=/sw --with-system-zlib --x-includes=/usr/X11R6/include --x-libraries=/usr/X11R6/lib --program-suffix=-fsf-4.7 --enable-checking=release --enable-cloog-backend=isl results in the linkage failure... ../../gcc-4.7-20110811/gcc/vegcc -g -fkeep-inline-functions -DIN_GCC -W -Wall -Wwrite-strings -Wcast-qual -Wstrict-prototypes -Wmissing-prototypes -Wmissing-format-attribute -pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -Wold-style-definition -Wc++-compat -DHAVE_CONFIG_H -o gengtype \ gengtype.o gengtype-lex.o gengtype-parse.o gengtype-state.o version.o errors.o libcommon.a ../libcpp/libcpp.a ../libiberty/libiberty.a ../libdecnumber/libdecnumber.a libcommon.a ../libcpp/libcpp.a -lintl -L/sw/lib -liconv ../libiberty/libiberty.a ../libdecnumber/libdecnumber.a ... ld: duplicate symbol _fancy_abort in libcommon.a(diagnostic.o) and errors.o for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) make[3]: *** [gengtype] Error 1 ... make[2]: *** [all-stage1-gcc] Error 2 make[1]: *** [stage1-bubble] Error 2 So we can not really ignore this PR as it breaks --enable-checking=release. Note that lto is not required for this failure mode.