Index: configure --- configure.orig 2019-02-02 10:19:54.528732000 +0100 +++ configure 2019-02-02 10:21:26.056722000 +0100 @@ -12669,7 +12669,6 @@ LDFLAGS="$LIBS $LIBM $LDFLAGS" -CFLAGS="-Wall $CFLAGS" ac_ext=cpp ac_cpp='$CXXCPP $CPPFLAGS' @@ -16371,7 +16370,7 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu -CXXFLAGS="-Wall -Wno-unused-function -DNDEBUG -O3 -fomit-frame-pointer $CXXFLAGS" +CXXFLAGS="-Wno-unused-function -DNDEBUG -O2 -fomit-frame-pointer $CXXFLAGS" # Check whether --enable-cxxmph was given. if test "${enable_cxxmph+set}" = set; then : enableval=$enable_cxxmph; case "${enableval}" in