stop attempting to suppress double '-O?' with --enable-debug

Similar to the prior commit, there is little advantage to these error prone
gymnastics when the compiler is perfectly happy to let a later option supersede
an earlier one. Note that for compilers that are not GCC or ICC, this means
there optimization flags are no longer altered when passing `--enable-debug`.

Related to #2115.

diff --git a/configure.ac b/configure.ac
index aae527bf39c9b1a5d713d596bdbf1eb2f280749a..b6778b49d22da725f8c80b0646e7c8482373794d 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -411,10 +411,6 @@ AC_ARG_ENABLE([debug],
        [enable_debug=no])
 AM_CONDITIONAL([DEBUG], [test $enable_debug = "yes"])
 if test "x$enable_debug" = "xyes"; then
-  changequote({,})
-  CFLAGS=`echo "$CFLAGS" | $SED -e 's/-O[0-9s]*//g'`
-  CXXFLAGS=`echo "$CXXFLAGS" | $SED -e 's/-O[0-9s]*//g'`
-  changequote([,])
   dnl add -O0 only if GCC or ICC is used
   if test "$GCC" = "yes" || test "$ICC" = "yes"; then
     CFLAGS="$CFLAGS -g -O0 -Wall"