Fix run command environment

Reuse Exec command logic for getting paths to all dependency binaries
and add those to PATH. As far as I understand, this can only add more
than `build-tool-depends` required.

cabal-install/src/Distribution/Client/CmdExec.hs

@@ -12,6 +12,8 @@
 module Distribution.Client.CmdExec
   ( execAction
   , execCommand
+  -- Utility function exposed for run command
+  , pathAdditions
   ) where
 
 import Distribution.Client.DistDirLayout
@@ -263,6 +265,12 @@ withTempEnvFile verbosity baseCtx buildCtx buildStatus action = do
         action envOverrides
     )
 
+-- | Get paths to all dependency executables to be included in PATH.
+--
+-- The filepaths need to be passed to the executable for example
+-- by 'modifyProgramSearchPath' if you are using 'ProgramDb'
+-- or more directly by passing them to 'progInvokePathEnv'
+-- if you are using 'ProgramInvocation'.
 pathAdditions :: Verbosity -> ProjectBaseContext -> ProjectBuildContext -> IO [FilePath]
 pathAdditions verbosity ProjectBaseContext{..} ProjectBuildContext{..} = do
   info verbosity . unlines $

cabal-install/src/Distribution/Client/CmdRun.hs

@@ -35,6 +35,7 @@ import Distribution.Client.CmdErrorMessages
   , targetSelectorFilter
   , targetSelectorPluralPkgs
   )
+import Distribution.Client.CmdExec (pathAdditions)
 import Distribution.Client.Errors
 import Distribution.Client.GlobalFlags
   ( defaultGlobalFlags
@@ -230,6 +231,9 @@ runAction flags@NixStyleFlags{..} targetAndArgs globalFlags =
                 elaboratedPlan
         return (elaboratedPlan', targets)
 
+    -- Some dependencies may have executables. Let's put those on the PATH.
+    extraPaths <- pathAdditions verbosity baseCtx buildCtx
+
     (selectedUnitId, selectedComponent) <-
       -- Slight duplication with 'runProjectPreBuildPhase'.
       singleExeOrElse
@@ -300,6 +304,7 @@ runAction flags@NixStyleFlags{..} targetAndArgs globalFlags =
                 dataDirsEnvironmentForPlan
                   (distDirLayout baseCtx)
                   elaboratedPlan
+            , progInvokePathEnv = extraPaths
             }
   where
     (targetStr, args) = splitAt 1 targetAndArgs