diff --git a/configure b/configure index 67ae35cec27..167483718e0 100755 --- a/configure +++ b/configure @@ -5561,6 +5561,49 @@ $as_echo "$ac_cv_no_strict_aliasing" >&6; } BASECFLAGS="$BASECFLAGS -fno-strict-aliasing" fi + { $as_echo "$as_me:${as_lineno-$LINENO}: checking if we can turn off $CC unused result warning" >&5 +$as_echo_n "checking if we can turn off $CC unused result warning... " >&6; } + ac_save_cc="$CC" + CC="$CC -Wunused-result -Werror" + save_CFLAGS="$CFLAGS" + if ${ac_cv_disable_unused_result_warning+:} false; then : + $as_echo_n "(cached) " >&6 +else + cat confdefs.h - <<_ACEOF >conftest.$ac_ext +/* end confdefs.h. */ + + +int +main () +{ + + ; + return 0; +} + +_ACEOF +if ac_fn_c_try_compile "$LINENO"; then : + + ac_cv_disable_unused_result_warning=yes + +else + + ac_cv_disable_unused_result_warning=no + +fi +rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext +fi + + CFLAGS="$save_CFLAGS" + CC="$ac_save_cc" + { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_disable_unused_result_warning" >&5 +$as_echo "$ac_cv_disable_unused_result_warning" >&6; } + + if test $ac_cv_disable_unused_result_warning = yes + then + BASECFLAGS="$BASECFLAGS -Wno-unused-result" + fi + # if using gcc on alpha, use -mieee to get (near) full IEEE 754 # support. Without this, treatment of subnormals doesn't follow # the standard. diff --git a/configure.in b/configure.in index 315a83234ea..d5f00b2dd59 100644 --- a/configure.in +++ b/configure.in @@ -981,6 +981,28 @@ yes) BASECFLAGS="$BASECFLAGS -fno-strict-aliasing" fi + AC_MSG_CHECKING(if we can turn off $CC unused result warning) + ac_save_cc="$CC" + CC="$CC -Wunused-result -Werror" + save_CFLAGS="$CFLAGS" + AC_CACHE_VAL(ac_cv_disable_unused_result_warning, + AC_COMPILE_IFELSE( + [ + AC_LANG_PROGRAM([[]], [[]]) + ],[ + ac_cv_disable_unused_result_warning=yes + ],[ + ac_cv_disable_unused_result_warning=no + ])) + CFLAGS="$save_CFLAGS" + CC="$ac_save_cc" + AC_MSG_RESULT($ac_cv_disable_unused_result_warning) + + if test $ac_cv_disable_unused_result_warning = yes + then + BASECFLAGS="$BASECFLAGS -Wno-unused-result" + fi + # if using gcc on alpha, use -mieee to get (near) full IEEE 754 # support. Without this, treatment of subnormals doesn't follow # the standard.