Document common installation errors

[pfultz2]

On Ubuntu, users could see this:

x86_64-linux-gnu-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fno-strict-aliasing -Wdate-time -D_FORTIFY_SOURCE=2 -g -fstack-protector-strong -Wformat -Werror=format-security -fPIC -I/usr/include/python2.7 -c _posixsubprocess.c -o build/temp.linux-x86_64-2.7/_posixsubprocess.o
    _posixsubprocess.c:3:20: fatal error: Python.h: No such file or directory
    compilation terminated.
    error: command 'x86_64-linux-gnu-gcc' failed with exit status 1

Which needs the python-dev package installed.

[pfultz2]

On fedora there is also:

gcc: error: /usr/lib/rpm/redhat/redhat-hardened-cc1: No such file or directory

Which can be solved by installing the redhat-rpm-config package.