diff options
Diffstat (limited to 'autoconf')
| -rw-r--r-- | autoconf/configure.ac | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/autoconf/configure.ac b/autoconf/configure.ac index 243b2ceec9..7e710080ea 100644 --- a/autoconf/configure.ac +++ b/autoconf/configure.ac @@ -538,18 +538,21 @@ bypass these sanity checks.])]) dnl Note that libstdc++4.6 is known broken for C++11 builds. The errors dnl are sometimes deeply confusing though. Here we test for an obvious dnl incomplete feature in 4.6's standard library that was completed in - dnl 4.7's. - AC_MSG_CHECKING([whether Clang will select a modern C++ standard library]) - llvm_cv_old_cxxflags="$CXXFLAGS" - CXXFLAGS="$CXXFLAGS -std=c++0x" - AC_LINK_IFELSE([AC_LANG_SOURCE([[ + dnl 4.7's. We also have to disable this test if 'ENABLE_LIBCPP' is set + dnl because the enable flags don't actually fix CXXFLAGS, they rely on + dnl that happening in the Makefile. + if test "$ENABLE_LIBCPP" -eq 0 ; then + AC_MSG_CHECKING([whether Clang will select a modern C++ standard library]) + llvm_cv_old_cxxflags="$CXXFLAGS" + CXXFLAGS="$CXXFLAGS -std=c++0x" + AC_LINK_IFELSE([AC_LANG_SOURCE([[ #include <atomic> std::atomic<float> x(0.0f); int main() { return (float)x; } ]])], - [AC_MSG_RESULT([yes])], - [AC_MSG_RESULT([no]) - AC_MSG_ERROR([ + [AC_MSG_RESULT([yes])], + [AC_MSG_RESULT([no]) + AC_MSG_ERROR([ We detected a missing feature in the standard C++ library that was known to be missing in libstdc++4.6 and implemented in libstdc++4.7. There are numerous C++11 problems with 4.6's library, and we don't support GCCs or libstdc++ older @@ -558,7 +561,8 @@ standard library. If this error is incorrect or you need to force things to work, you may pass '--disable-compiler-version-checks' to configure to bypass this test.])]) - CXXFLAGS="$llvm_cv_old_cxxflags" + CXXFLAGS="$llvm_cv_old_cxxflags" + fi ;; gcc) AC_MSG_CHECKING([whether GCC is new enough]) |