dnl this magic incantation is needed to prevent AC_PROG_CC from setting the
dnl default CFLAGS (something like "-g -O2") - we don't need this as add
dnl -g and -O flags ourselves below
-CFLAGS=${CFLAGS=}
+CFLAGS=${CFLAGS:=}
AC_PROG_CC
dnl is -traditional needed for correct compilations
dnl defines CXXFLAGS
dnl
dnl see CFLAGS line above
-CXXFLAGS=${CXXFLAGS=}
+CXXFLAGS=${CXXFLAGS:=}
AC_PROG_CXX
AC_LANG_RESTORE