docs: explicitly list programs known to Cabal (fix #7899)

Author: ulysses4ever

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

@@ -61,6 +61,9 @@ import qualified Data.Map as Map
 
 -- ------------------------------------------------------------
 
+-- NOTE: if you modify the list of builtin programs below, also update documentation in
+-- the Cabal manual: option `--with-PROG` described in doc/setup-commands.rst
+
 -- | The default list of programs.
 -- These programs are typically used internally to Cabal.
 builtinPrograms :: [Program]

doc/setup-commands.rst

@@ -201,8 +201,11 @@ files of a package:
     name of a program that can be found on the program search path. For
     example: ``--with-ghc=ghc-6.6.1`` or
     ``--with-cpphs=/usr/local/bin/cpphs``. The full list of accepted
-    programs is not enumerated in this user guide. Rather, run
-    ``cabal install --help`` to view the list.
+    programs is as follows:
+    ``alex``, ``ar``, ``c2hs``, ``cpphs``, ``doctest``, ``gcc``, ``ghc``,
+    ``ghc-pkg``, ``ghcjs``, ``ghcjs-pkg``, ``haddock``, ``happy``,
+    ``hpc``, ``hsc2hs``, ``hscolour``, ``jhc``, ``ld``, ``pkg-config``,
+    ``runghc``, ``strip``, ``tar``, ``uhc``.
 
 .. option:: --PROG-options=OPTS