Bug option CXXFLAGS wrong configuration

tracy/configure.ac

 # Process this file with autoconf to produce a configure script.
-AC_INIT([Tracy], [3.0], [nadolski@synchrotron-soleil.fr])
+AC_INIT([Tracy], [3.10], [nadolski@synchrotron-soleil.fr])
 # Set auxilliary directory for config files
 AC_CONFIG_AUX_DIR(config)
 
@@ -96,7 +96,7 @@ case $target_os in
   linux-gnu)
     
     #Compilation optionss
-    CXXFLAGS="-O2 -Wall -fno-implicit-templates " # C++ options
+    CXXFLAGS="$CXXFLAGS -Wall -fno-implicit-templates " # C++ options
     CFLAGS="$CFLAGS -Wall-fno-implicit-templates "     # C   options 
     FFLAGS="$FFLAGS -Wall -fbounds-check" # Fortran options
     if test "x$HOSTNAME" = xisei; then
@@ -143,6 +143,7 @@ SYNCHROTRON SOLEIL
 
 Prefix.........: ${prefix}
 Compiler.......: ${CC} ${CFLAGS} ${CPPFLAGS}
+Compiler C++...: ${CXX} ${CXXFLAGS} ${CPPFLAGS}
 Debug Build....: ${debug}
 Libraries......: ${LIBS}