PR is welcome to (see the "Initial description" below if you need more detail on the issue)

1. inline the list of known programs that you can get from cabal v1-build --help (see the very bottom) into the docs,

2. add a NOTE on builtinPrograms (

   cabal/Cabal/src/Distribution/Simple/Program/Builtin.hs

   Lines 66 to 94 in f83f91e

   	builtinPrograms :: [Program]
   	builtinPrograms =
   	[ -- compilers and related progs
   	ghcProgram
   	, runghcProgram
   	, ghcPkgProgram
   	, ghcjsProgram
   	, ghcjsPkgProgram
   	, jhcProgram
   	, uhcProgram
   	, hpcProgram
   	, -- preprocessors
   	hscolourProgram
   	, doctestProgram
   	, haddockProgram
   	, happyProgram
   	, alexProgram
   	, hsc2hsProgram
   	, c2hsProgram
   	, cpphsProgram
   	, -- platform toolchain
   	gccProgram
   	, arProgram
   	, stripProgram
   	, ldProgram
   	, tarProgram
   	, -- configuration tools
   	pkgConfigProgram
   	]

   ) to update that place of the docs if this list is updated (I confirmed that what v1-build prints it takes from this list).

Initial description:

I'm unable to locate list of programs for which executables and options can be supplied via e.g. cabal configure --with-gcc=... --with-gcc-options=....

The manual at https://cabal.readthedocs.io/en/latest/setup-commands.html?highlight=--with-prog#cmdoption-runhaskell-Setup.hs-configure-with-prog directs to use cabal install --help. But there's no such info there:

$ cabal --version
cabal-install version 3.7
compiled using version 3.7.0.0 of the Cabal library 
$ cabal install --help
...
 --with-PROG=PATH               give the path to PROG
 --PROG-option=OPT              give an extra option to PROG (no need to quote
                                options containing spaces)
 --PROG-options=OPTS            give extra options to PROG
...

There's mention that it is possible but list of programs is nowhere to be found. For instance,cabal install --help | awk '/gcc|alex/' returns nothing but shouldn't since --with-gcc and --with-alex are accepted options so they should've been mentioned somewhere.

Now, I can find list of programs at ~/.cabal/config but that's probably not the way to do it. Perhaps the list should be enumerated in the Cabal User Guide?