# C++ checks to determine what style of headers to use and # whether to use "using" clauses. AC_DEFUN(AC_CXX_HAVE_STDHEADERS, [ AC_SUBST(cxx_have_stdheaders) AC_CACHE_CHECK([whether C++ supports the ISO C++ standard includes], db_cv_cxx_have_stdheaders, [AC_LANG_SAVE AC_LANG_CPLUSPLUS AC_TRY_COMPILE([#include ],[std::ostream *o; return 0;], db_cv_cxx_have_stdheaders=yes, db_cv_cxx_have_stdheaders=no) AC_LANG_RESTORE ]) if test "$db_cv_cxx_have_stdheaders" = yes; then cxx_have_stdheaders="#define HAVE_CXX_STDHEADERS 1" fi])