gcc 4.9.2 installation Mac OS X 10.7.5

[jomarbueyes]

Hi 

I'm not sure this is the right forum for these questions. It it is not, could 
someone point me to the right forum?

I'm trying to install the GNU compiler collection version 4.9.2(gcc-4.9.2) on 
an Intel Mac running 10.7.5 (Lion). I would like to first install not in the 
usual /usr/bin/... hierarchy. I've been reading the configuration instructions 
in https://gcc.gnu.org/install/configure.html but there are a few optional 
directories that I don't fully understand. These are:

    --with-local-prefix
    --with-native-system-header
    --with-gnu-as
    --with-as
    --with-gnu-ld
    --with-ld
    --with-libiconv-prefix

The description under --with-local-prefix reads:

"Specify the installation directory for local include files. The default is 
/usr/local. Specify this option if you want the compiler to search directory 
dirname/include for locally installed header files instead of 
/usr/local/include."

The description for other directories in the list above is similar.

What is not clear to me is whether after installation the new compiler will 
search this directory or the compiler that is compiling the new gcc will look 
for files there to build the updated compilers.

As I mentioned above, if this is not the right forum for this question, could 
someone point me to a better suited forum?

Thank you in advance for any help,

Jomar 
(cross-posted to gnu.gcc and gnu.gcc.help)