tests: diff -u is not portable

[bison.git] / tests / existing.at

diff --git a/tests/existing.at b/tests/existing.at
index 582f6b3df6f7747c2da9a0324998f392c7d35fc0..149499d4bac90965ea4d3f874334e6530d936aea 100644 (file)
--- a/tests/existing.at
+++ b/tests/existing.at
@@ -35,7 +35,10 @@ dnl time comes, just use sed to drop the line numbers.  For now, as LR(1)
 dnl support is rapidly evolving, let's keep that information to be careful.
 dnl However, we don't do diffs for canonical LR(1) because the diff is huge.
 m4_pushdef([AT_LALR1_DIFF_CHECK],
-[AT_CHECK([[sed 's/^%define lr.type .*$//' input.y > input-lalr.y]])
+[dnl We need diff -u, which is not portable.
+AT_CHECK([diff -u /dev/null /dev/null || exit 77], [0], [ignore])
+
+AT_CHECK([[sed 's/^%define lr.type .*$//' input.y > input-lalr.y]])
 AT_BISON_CHECK([[--report=all input-lalr.y]], [[0]], [ignore], [ignore])
 AT_CHECK([[diff -u input-lalr.output input.output \
            | sed -n '/^@@/,$p' | sed 's/^ $//']],