https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111638
--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:898fd81b831c106859bc99e65c7c1cbb642320c8 commit r14-5342-g898fd81b831c106859bc99e65c7c1cbb642320c8 Author: Jonathan Wakely <jwak...@redhat.com> Date: Fri Sep 29 14:29:16 2023 +0100 libstdc++: Remove handling for underscore-prefixed libm functions [PR111638] The checks in linkage.m4 try to support math functions prefixed with underscores, like _acosf and _isinf. However, that doesn't work because they're renamed to the standard names using a macro, but then <cmath> undefines that macro again. This simply removes everything related to those underscored functions. libstdc++-v3/ChangeLog: PR libstdc++/111638 * config.h.in: Regenerate. * configure: Regenerate. * linkage.m4 (GLIBCXX_MAYBE_UNDERSCORED_FUNCS): Remove. (GLIBCXX_CHECK_MATH_DECL_AND_LINKAGE_1): Do not check for _foo. (GLIBCXX_CHECK_MATH_DECLS_AND_LINKAGES_1): Likewise. (GLIBCXX_CHECK_MATH_DECL_AND_LINKAGE_2): Likewise. (GLIBCXX_CHECK_MATH_DECL_AND_LINKAGE_3): Likewise. (GLIBCXX_CHECK_STDLIB_DECL_AND_LINKAGE_2): Do not use GLIBCXX_MAYBE_UNDERSCORED_FUNCS.