+dnl Usage: LYX_CXX_CXX11: set lyx_use_cxx11 to yes if the compiler implements
+dnl the C++11 standard.
+AC_DEFUN([LYX_CXX_CXX11],
+[AC_CACHE_CHECK([whether the compiler implements C++11],
+ [lyx_cv_cxx_cxx11],
+ [save_CPPFLAGS=$CPPFLAGS
+ CPPFLAGS="$AM_CPPFLAGS $CPPFLAGS"
+ save_CXXFLAGS=$CXXFLAGS
+ CXXFLAGS="$AM_CXXFLAGS $CXXFLAGS"
+ AC_LANG_PUSH(C++)
+ AC_TRY_COMPILE([], [
+#if __cplusplus >= 201103L || defined(__GXX_EXPERIMENTAL_CXX0X__)
+ this is a c++11 compiler
+#endif
+ ],
+ [lyx_cv_cxx_cxx11=no], [lyx_cv_cxx_cxx11=yes ; lyx_flags="$lyx_flags c++11"])
+ AC_LANG_POP(C++)
+ CXXFLAGS=$save_CXXFLAGS
+ CPPFLAGS=$save_CPPFLAGS])
+ lyx_use_cxx11=$lyx_cv_cxx_cxx11
+])
+
+
+dnl Usage: LYX_CXX_USE_REGEX(cxx11_flags)
+dnl decide whether we want to use std::regex and set the
+dnl LYX_USE_STD_REGEX accordingly.
+dnl the extra cxx11 flags have to be passed to the preprocessor. They are
+dnl not plainly added to AM_CPPFLAGS because then the objc compiler (mac)
+dnl would fail.
+AC_DEFUN([LYX_CXX_USE_REGEX],
+[lyx_std_regex=no
+ if test $lyx_use_cxx11 = yes; then
+ save_CPPFLAGS=$CPPFLAGS
+ # we want to pass -std=c++11 to clang/cpp if necessary
+ CPPFLAGS="$AM_CPPFLAGS $1 $CPPFLAGS"
+ save_CXXFLAGS=$CXXFLAGS
+ CXXFLAGS="$AM_CXXFLAGS $CXXFLAGS"
+ AC_LANG_PUSH(C++)
+ AC_CHECK_HEADER([regex], [lyx_std_regex=yes], [lyx_std_regex=no])
+ AC_LANG_POP(C++)
+ CXXFLAGS=$save_CXXFLAGS
+ CPPFLAGS=$save_CPPFLAGS
+ if test x$GXX = xyes && test $lyx_std_regex = yes ; then
+ AC_MSG_CHECKING([for correct regex implementation])
+ if test x$CLANG = xno || test $lyx_cv_lib_stdcxx = yes; then
+ dnl <regex> in gcc is unusable in versions less than 4.9.0
+ dnl see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53631
+ case $gxx_version in
+ 4.0*|4.1*|4.2*|4.3*|4.4*|4.5*|4.6*|4.7*|4.8*) lyx_std_regex=no ;;
+ *) ;;
+ esac
+ fi
+ fi
+ AC_MSG_RESULT([$lyx_std_regex])
+ fi
+
+ if test $lyx_std_regex = yes ; then
+ lyx_flags="$lyx_flags std-regex"
+ AC_DEFINE([LYX_USE_STD_REGEX], 1, [define to 1 if std::regex should be preferred to boost::regex])
+ fi
+ AM_CONDITIONAL([LYX_USE_STD_REGEX], test $lyx_std_regex = yes)
+])
+
+