| dnl AX_CXXFLAGS_OPTIONS(var-name, option) |
| dnl add option to var-name if $CXX support it. |
| AC_DEFUN([AX_CHECK_PRECOMPILED_HEADER], [ |
| AC_MSG_CHECKING([whether ${CXX} support precompiled header]) |
| AC_LANG_SAVE |
| AC_LANG_CPLUSPLUS |
| SAVE_CXXFLAGS=$CXXFLAGS |
| dnl we consider than if -Winvalid-pch is accepted pch will works ... |
| CXXFLAGS=-Winvalid-pch |
| dnl but we don't want -Winvalid-pch else compilation will fail due -Werror and |
| dnl the fact than some pch will be invalid for the given compilation option |
| AC_TRY_COMPILE(,[;],AC_MSG_RESULT([yes]); $1="${$1} -include bits/stdc++.h", AC_MSG_RESULT([no])) |
| CXXFLAGS=$SAVE_CXXFLAGS |
| AC_LANG_RESTORE |
| ]) |
