autoconf: remove obsolete patch detection

This commit removes obsolete deletection logic of the patch command
from autoconf scripts, given we no longer need to patch anything in
the GHC build process.

(cherry picked from commit 71f28958)

configure.ac

@@ -735,10 +735,6 @@ dnl ** check for tar
 dnl   if GNU tar is named gtar, look for it first.
 AC_PATH_PROGS(TarCmd,gnutar gtar tar,tar)
 
-dnl ** check for patch
-dnl if GNU patch is named gpatch, look for it first
-AC_PATH_PROGS(PatchCmd,gpatch patch, patch)
-
 dnl ** check for autoreconf
 AC_PATH_PROG(AutoreconfCmd, autoreconf, autoreconf)
 

hadrian/cfg/system.config.in

@@ -17,7 +17,6 @@ sphinx-build   = @SPHINXBUILD@
 system-ghc     = @WithGhc@
 system-ghc-pkg = @GhcPkgCmd@
 tar            = @TarCmd@
-patch          = @PatchCmd@
 xelatex        = @XELATEX@
 makeindex      = @MAKEINDEX@
 makeinfo       = @MAKEINFO@