diff --git a/configure.ac b/configure.ac
index ece2118b7b8f347bdaf776078a71b8ff4a9e6198..5ab4cb141716aa1be7728d510a97d2b6c83e1f19 100644
--- a/configure.ac
+++ b/configure.ac
@@ -734,9 +734,6 @@ AC_SUBST(TargetHasIdentDirective)
 GHC_GNU_NONEXEC_STACK
 AC_SUBST(TargetHasGnuNonexecStack)
 
-dnl ** figure out how to do context diffs
-FP_PROG_CONTEXT_DIFF
-
 dnl Let's make sure install-sh is executable here.  If we got it from
 dnl a darcs repo, it might not be (see bug #978).
 chmod +x install-sh
diff --git a/m4/fp_prog_context_diff.m4 b/m4/fp_prog_context_diff.m4
deleted file mode 100644
index 886f73ce4c0baf0bf39d31ce0771ca544a0b7548..0000000000000000000000000000000000000000
--- a/m4/fp_prog_context_diff.m4
+++ /dev/null
@@ -1,23 +0,0 @@
-# FP_PROG_CONTEXT_DIFF
-# --------------------
-# Figure out how to do context diffs. Sets the output variable ContextDiffCmd.
-#
-# Note: NeXTStep thinks diff'ing a file against itself is "trouble".
-AC_DEFUN([FP_PROG_CONTEXT_DIFF],
-[AC_CACHE_CHECK([for a working context diff], [fp_cv_context_diff],
-[echo foo > conftest1
-echo foo > conftest2
-fp_cv_context_diff=no
-for fp_var in '-U 1' '-u1' '-C 1' '-c1'
-do
-  if diff $fp_var conftest1 conftest2 > /dev/null 2>&1; then
-    fp_cv_context_diff="diff $fp_var"
-    break
-  fi
-done])
-if test x"$fp_cv_context_diff" = xno; then
-   AC_MSG_ERROR([cannot figure out how to do context diffs])
-fi
-AC_SUBST(ContextDiffCmd, [$fp_cv_context_diff])
-])# FP_PROG_CONTEXT_DIFF
-