Here are the gory details about some utility programs you may need; perl, gcc and happy are the only important ones. (PVM is important if you're going for Parallel Haskell.) The configure script will tell you if you are missing something.
You have to have Perl to proceed! It is pretty easy to install.
Perl 5 is required. For Win32 platforms, you should use the binary supplied in the InstallShield (copy it to /bin). The Cygwin-supplied Perl seems not to work.
Perl should be put somewhere so that it can be invoked by the #! script-invoking mechanism. The full pathname may need to be less than 32 characters long on some systems.
We recommend using GCC version 2.95.2 on all platforms. Failing that, version 2.7.2 is stable on most platforms. Earlier versions of GCC can be assumed not to work, and versions in between 2.7.2 and 2.95.2 (including egcs) have varying degrees of stability depending on the platform.
If your GCC dies with ``internal error'' on some GHC source file, please let us know, so we can report it and get things improved. (Exception: on iX86 boxes—you may need to fiddle with GHC's -monly-N-regs option; see the User's Guide)
Happy is a parser generator tool for Haskell, and is used to generate GHC's parsers. Happy is written in Haskell, and is a project in the CVS repository (fptools/happy). It can be built from source, but bear in mind that you'll need GHC installed in order to build it. To avoid the chicken/egg problem, install a binary distribtion of either Happy or GHC to get started. Happy distributions are available from Happy's Web Page.
GNU Autoconf is needed if you intend to build from the CVS sources, it is not needed if you just intend to build a standard source distribution.
Autoconf builds the configure script from configure.in and aclocal.m4. If you modify either of these files, you'll need autoconf to rebuild configure.
You need a working sed if you are going to build from sources. The build-configuration stuff needs it. GNU sed version 2.0.4 is no good! It has a bug in it that is tickled by the build-configuration. 2.0.5 is OK. Others are probably OK too (assuming we don't create too elaborate configure scripts.)
One fptools project is worth a quick note at this point, because it is useful for all the others: glafp-utils contains several utilities which aren't particularly Glasgow-ish, but Occasionally Indispensable. Like lndir for creating symbolic link trees.
PVM is the Parallel Virtual Machine on which Parallel Haskell programs run. (You only need this if you plan to run Parallel Haskell. Concurent Haskell, which runs concurrent threads on a uniprocessor doesn't need it.) Underneath PVM, you can have (for example) a network of workstations (slow) or a multiprocessor box (faster).
The current version of PVM is 3.3.11; we use 3.3.7. It is readily available on the net; I think I got it from research.att.com, in netlib.
A PVM installation is slightly quirky, but easy to do. Just follow the Readme instructions.
Sadly, the gr2ps script, used to convert ``parallelism profiles'' to PostScript, is written in Bash (GNU's Bourne Again shell). This bug will be fixed (someday).
The following additional tools are required if you want to format the documentation that comes with the fptools projects:
All our documentation is written in SGML, using the DocBook DTD. Instructions on installing and configuring the DocBook tools are in the installation guide (in the GHC user guide).
A decent TeX distribution is required if you want to produce printable documentation. We recomment teTeX, which includes just about everything you need.
This is a quite-a-bit-better-than-Lex lexer. Used to build a couple of utilities in glafp-utils. Depending on your operating system, the supplied lex may or may not work; you should get the GNU version.