From f0b74640137f07ed74027f98fbf6d1c0d98939bf Mon Sep 17 00:00:00 2001 From: Stephan Bergmann Date: Mon, 20 Apr 2020 11:40:24 +0200 Subject: Add --with-latest-c++ to explicitly opt in for -std=c++20/-std:c++latest Adaptation of this change to this branch. The point is to avoid compiling as C++2a as the code for externals has not been patched properly for that here. Here is the original commit message even if I assume it is a bit misleading in this branch: cd472d1d8489f30797f47d3f6dafede28c1feb90 "Compile as C++2a, where available" had started to unconditionally check for support of -std=c++2a (and later also -std=c++20) for Clang and GCC, but that can cause occasional issues especially for Linux distros, see e.g. 55c724b93dfd4c9a1afb10d60fbc2d7a9a66cf61 "replace boost::bimap in sdext pdfimport" or "/usr/include/boost/format/alt_sstream_impl.hpp incompatible with -std=c++20 (std::allocator::allocate hint argument)" (where 677c8de4fa79cd9b278b142013ba7f1c9e4e41c3 "external/boost: Adapt to std::allocator parts removed in C++20" is not picked up due to --with-system-boost). So better require an explicit opt-in via a new --with-latest-c++. And while at it, also make that enable -std:c++latest for MSVC. Change-Id: I2d1f03144fad9a7884562e56b1b76cab5eb8f080 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/92555 Tested-by: Jenkins Reviewed-by: Stephan Bergmann Reviewed-on: https://gerrit.libreoffice.org/c/core/+/93204 Tested-by: Jenkins CollaboraOffice Reviewed-by: Tor Lillqvist Reviewed-on: https://gerrit.libreoffice.org/c/core/+/93692 Tested-by: Tor Lillqvist --- configure.ac | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/configure.ac b/configure.ac index 78080305f3d6..8364138bdc96 100644 --- a/configure.ac +++ b/configure.ac @@ -2143,6 +2143,12 @@ libo_FUZZ_ARG_WITH(lxml, report widget classes and ids.]), ,) +libo_FUZZ_ARG_WITH(latest-c++, + AS_HELP_STRING([--with-latest-c++], + [Try to enable the latest features of the C++ compiler, even if they are not yet part of a + published standard.]),, + [$with_latest_c__=no]) + dnl =================================================================== dnl Branding dnl =================================================================== @@ -6456,9 +6462,17 @@ dnl =================================================================== AC_MSG_CHECKING([whether $CXX_BASE supports C++17]) CXXFLAGS_CXX11= if test "$COM" = MSC -a "$COM_IS_CLANG" != TRUE; then - CXXFLAGS_CXX11='-std:c++17 -Zc:__cplusplus' + if test "$with_latest_c__" = yes; then + CXXFLAGS_CXX11=-std:c++latest + else + CXXFLAGS_CXX11=-std:c++17 + fi + CXXFLAGS_CXX11="$CXXFLAGS_CXX11 -Zc:__cplusplus" elif test "$GCC" = "yes" -o "$COM_IS_CLANG" = TRUE; then - my_flags='-std=c++2a -std=c++17 -std=c++1z' + my_flags='-std=c++17 -std=c++1z' + if test "$with_latest_c__" = yes; then + my_flags="-std=gnu++2a -std=c++2a $my_flags" + fi for flag in $my_flags; do if test "$COM" = MSC; then flag="-Xclang $flag" -- cgit v1.2.1