--- a/configure
+++ b/configure
@@ -2659,11 +2659,9 @@
      ;;
      *:*)                   # Simple initialization syntax
        CXX=`echo "$cxxwith" | sed  -n -e 's/.*:\(.*\)/\1/p'`
-       CXXFLAGS=""
      ;;
      *)                     # Default values
        CXX="g++"
-       CXXFLAGS=""
      ;;
    esac
        CXX_OPTIMIZE_FLAGS="-DTVMET_OPTIMIZE -O2 -finline-limit=5000 -ftemplate-depth-200 -fomit-frame-pointer"
@@ -3704,7 +3702,6 @@
   echo "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
-	CXXFLAGS=""
       cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -3799,15 +3796,9 @@
   CXXFLAGS=$ac_save_CXXFLAGS
 elif test $ac_cv_prog_cxx_g = yes; then
   if test "$GXX" = yes; then
-    CXXFLAGS="-g -O2"
+    CXXFLAGS+="$CXXFLAGS -g -O2"
   else
-    CXXFLAGS="-g"
-  fi
-else
-  if test "$GXX" = yes; then
-    CXXFLAGS="-O2"
-  else
-    CXXFLAGS=
+    CXXFLAGS+="$CXXFLAGS -g"
   fi
 fi
 ac_ext=cpp