1 dnl AX_CXXFLAGS_OPTIONS(var-name, option) 2 dnl add option to var-name if $CXX support it. 3 AC_DEFUN([AX_CHECK_PRECOMPILED_HEADER], [ 4 AC_MSG_CHECKING([whether ${CXX} support precompiled header]) 5 AC_LANG_SAVE 6 AC_LANG_CPLUSPLUS 7 SAVE_CXXFLAGS=$CXXFLAGS 8 dnl we consider than if -Winvalid-pch is accepted pch will works ... 9 CXXFLAGS=-Winvalid-pch 10 dnl but we don't want -Winvalid-pch else compilation will fail due -Werror and 11 dnl the fact than some pch will be invalid for the given compilation option 12 AC_TRY_COMPILE(,[;],AC_MSG_RESULT([yes]); $1="${$1} -include bits/stdc++.h", AC_MSG_RESULT([no])) 13 CXXFLAGS=$SAVE_CXXFLAGS 14 AC_LANG_RESTORE 15 ]) 16
