MacOS – Can’t install mercurial on Mac OS X

Just add /opt/local/bin to your path, like the rest of us. You can do this in ~/.profile

Trying to force it to /usr/local/bin

• is an unnecessary effort
• risks executable or library collisions with evil and a potentially disastrous impact

First answer: Don't! In my experience, GCC 4.4.3 will not work properly on Snow Leopard. It will cause problems with zero-length strings.

Second answer: edit your symbolic links in /usr/bin to refer to the 4.4 stuff. Here's a script I wrote to do so:

rm /usr/bin/c++ 
ln -s /usr/bin/c++-${1} /usr/bin/c++
rm /usr/bin/cc
ln -s /usr/bin/cc-${1} /usr/bin/cc
rm /usr/bin/cpp
ln -s /usr/bin/cpp-${1} /usr/bin/cpp
rm /usr/bin/g++
ln -s /usr/bin/g++-${1} /usr/bin/g++
rm /usr/bin/gcc
ln -s /usr/bin/gcc-${1} /usr/bin/gcc
rm /usr/bin/gcov
ln -s /usr/bin/gcov-${1} /usr/bin/gcov

I called it chgCver, so to change my compiler to 4.4, I'd type chgCver 4.4. Of course, before you run this, you'll also need to make sure that, for example, c++-4.4 points to the correct place (probably /opt/local/bin/gcc-mp-4.4), etc. I can give you more specifics, if you're inclined to ignore my first and third answers.

Third answer: Don't! (See first answer.)