“I just want to build it!”
No problem. This recipe should build and install a working GHC with all the default settings. (unless you're on Windows, in which case go to Section 12, “Instructions for building under Windows”).
$ autoreconf $ ./configure $ make $ make install
For GHC, this will do a 2-stage bootstrap build of the
compiler, with profiling libraries, and install the
results in the default location (under
Unix, for example).
configure script is a standard GNU
autoconf script, and accepts the usual options for
changing install locations and the like. Run
./configure --help for a list of options.
If you want to do anything at all non-standard, or you want to do some development, read on...
 not necessary if you started from a source tarball