constant: don't skip the E2BIG test on Hurd, but improve comments

As Father Chrysostomos explained on [perl #128319] the previous change
was based on a misunderstanding of the purpose of the test, which is
only to test that constant.pm can create a dualvar out of $! which
has an error string, and nothing specifically to do with E2BIG.

The new comments, also suggested by Father Chrysostomos, make this more
clear.

1 files changed, 7 insertions, 8 deletions

diff --git a/dist/constant/t/constant.t b/dist/constant/t/constant.t
index 6bf0da95aa..442b81963c 100644
--- a/dist/constant/t/constant.t
+++ b/dist/constant/t/constant.t
@@ -92,14 +92,13 @@ is ZERO3, '0.0';
 cmp_ok(abs(PI - 3.1416), '<', 0.0001);
 is Other::PI, 3.141;
 
-SKIP: {
-    skip "GNU/Hurd doesn't use 7 as E2BIG", 2 if $^O eq "gnu";
-    use constant E2BIG => $! = 7;
-    cmp_ok E2BIG, '==', 7;
-    # This is something like "Arg list too long", but the actual message
-    # text may vary, so we can't test much better than this.
-    cmp_ok length(E2BIG), '>', 6;
-}
+# Test that constant.pm can create a dualvar out of $!
+use constant A_DUALVAR_CONSTANT => $! = 7;
+cmp_ok A_DUALVAR_CONSTANT, '==', 7;
+# Make sure we have an error message string.  It does not
+# matter that 7 means different things on different platforms.
+# If this test fails, then either constant.pm or $! is broken:
+cmp_ok length(A_DUALVAR_CONSTANT), '>', 6;
 
 is @warnings, 0 or diag join "\n- ", "unexpected warning:", @warnings;
 @warnings = ();		# just in case