If you want to change the compilation flags:
set in your environment a variable called CXXFLAGS
with the flags you want, before launching the configure
script.

example:
setenv CXXFLAGS "-g -Wall"
if you don't want the flags -02 to be set for debugging purposes.

You can also change your gcc version if you have multiple
versions installed
example:
setenv CXX g++3
setenv CC gcc3

note:
If you change your CXXFLAGS you will have to launch the configure
script again to regenerate the Makefiles.
