configure.in (make_compare_target): Test for GNU cmp and set this variable appropriately.

[thirdparty/gcc.git] / gcc / configure.in

diff --git a/gcc/configure.in b/gcc/configure.in
index fefc7a1555e46fbbda926e806c0408c9c18521c6..03f65867f0c3a29d8ceacbcf342f94be53ea5227 100644 (file)
--- a/gcc/configure.in
+++ b/gcc/configure.in
@@ -645,6 +645,17 @@ else
   GENERATED_MANPAGES=
 fi
 
+# If GNU cmp is present and recent enough, 'make compare' can be
+# significantly faster.
+gcc_AC_CHECK_PROG_VER(gnucmp, cmp, --version,
+  [(GNU diffutils) \([0-9][0-9.]*\)], [2.[4-9]*])
+if test $gcc_cv_prog_cmp_modern = yes; then
+  make_compare_target=gnucompare
+else
+  make_compare_target=slowcompare
+fi
+AC_SUBST(make_compare_target)
+
 # How about lex?
 dnl Don't use AC_PROG_LEX; we insist on flex.
 dnl LEXLIB is not useful in gcc.