Installing python library matplotlib on RedHat for second python installation

I built from source. :( Surprisingly not that difficult, but ran into a lot of problems doing the interactive part (Redhat 4 is too old to have packages for most things that let you do interactive backends, I need a newer machine).

# get matplotlib
wget https://downloads.sourceforge.net/project/matplotlib/matplotlib/matplotlib-1.4.3/matplotlib-1.4.3.tar.gz

#uncompress
tar xvzf matplotlib-1.4.3.tar.gz

# open build install
# read INSTALL file for more instructions
cd matplotlib-1.4.3
python setup.py build
# actually installing needed superuser privileges
sudo python setup.py install

Hope this saves time for anyone else with a similar setup.

NOTE:

I tried what @Anthon said to do! but it didn't work very well because of the age of my OS? pip assumes some things that didn't work well for some annoying reason. I tried to use pip2.7 instead, installed all the required dependencies, and it broke on this issue concerning permissions. The solution is to reset the permissions of the problem file with:

chmod o+x /path/to/file

However, it's a temporary copied file. :( During the install of matplotlib it recopies this file over, so I can't set permissions on it. Here is the place it is broken:

g++ ... -lpython2.7 -o build/lib.linux-x86_64-2.7/matplotlib/backends/_backend_agg.so
running install_lib
copying pylab.py -> /usr/lib64/python2.7/site-packages
error: [Errno 13] Permission denied: '/usr/lib64/python2.7/site-packages/pylab.py'

This doesn't seem like the right way to do it, it's too cobbled together. Final solution to avoid all this is the start of this answer.