Revert "New method for checking for presence of tex program."

This reverts commit 285bbf61cf.

pandoc.cabal

@@ -425,8 +425,7 @@ Executable pandoc
                  aeson >= 0.7.0.5 && < 0.12,
                  yaml >= 0.8.8.2 && < 0.9,
                  containers >= 0.1 && < 0.6,
-                 HTTP >= 4000.0.5 && < 4000.4,
-                 process >= 1.0 && < 1.5
+                 HTTP >= 4000.0.5 && < 4000.4
   if flag(network-uri)
      Build-Depends: network-uri >= 2.6 && < 2.7, network >= 2.6
   else

pandoc.hs

@@ -52,7 +52,6 @@ import Data.Char ( toLower, toUpper )
 import Data.List ( delete, intercalate, isPrefixOf, isSuffixOf, sort )
 import System.Directory ( getAppUserDataDirectory, findExecutable,
                           doesFileExist, Permissions(..), getPermissions )
-import System.Process ( readProcessWithExitCode )
 import System.IO ( stdout, stderr )
 import System.IO.Error ( isDoesNotExistError )
 import qualified Control.Exception as E
@@ -1402,11 +1401,8 @@ convertWithOpts opts args = do
                               _ | html5Output   -> "wkhtmltopdf"
                               _                 -> latexEngine
               -- check for pdf creating program
-              (ec,_,_) <- E.catch
-                          (readProcessWithExitCode pdfprog ["--version"] "")
-                          (\(_ :: E.SomeException) ->
-                              return (ExitFailure 1,"",""))
-              when (ec /= ExitSuccess) $
+              mbPdfProg <- findExecutable pdfprog
+              when (isNothing mbPdfProg) $
                    err 41 $ pdfprog ++ " not found. " ++
                      pdfprog ++ " is needed for pdf output."