https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78087
--- Comment #1 from Jack Howarth <howarth.at.gcc at gmail dot com> --- Interestingly, the stock build of gcc 6.2.0 on x86_64 linux (with LTO plugin linker plugin support) runs into a different set of failures when building emacs 25.1 using '-O0 -flto'... CCLD etags /tmp/ccS55vep.ltrans4.ltrans.o: In function `skip_spaces.lto_priv.60': /home/howarth/emacs-25.1/build/lib-src/../../lib-src/etags.c:6677: undefined reference to `c_isspace' /tmp/ccS55vep.ltrans4.ltrans.o: In function `skip_non_spaces.lto_priv.71': /home/howarth/emacs-25.1/build/lib-src/../../lib-src/etags.c:6686: undefined reference to `c_isspace' ... /home/howarth/emacs-25.1/build/lib-src/../../lib-src/etags.c:1209: undefined reference to `rpl_optind' /home/howarth/emacs-25.1/build/lib-src/../../lib-src/etags.c:1263: undefined reference to `set_binary_mode' collect2: error: ld returned 1 exit status or using '-O2 -flto'... CCLD etags /tmp/ccaauRE2.ltrans1.ltrans.o: In function `strcaseeq': /home/howarth/emacs-25.1/build/lib-src/../../lib-src/etags.c:162: undefined reference to `c_strcasecmp' /home/howarth/emacs-25.1/build/lib-src/../../lib-src/etags.c:162: undefined reference to `c_strcasecmp' /tmp/ccaauRE2.ltrans1.ltrans.o: In function `main': ... /home/howarth/emacs-25.1/build/lib-src/../../lib-src/etags.c:174: undefined reference to `c_strncasecmp' /tmp/ccaauRE2.ltrans4.ltrans.o:/home/howarth/emacs-25.1/build/lib-src/../../lib-src/etags.c:174: more undefined references to `c_strncasecmp' follow collect2: error: ld returned 1 exit status
