Correct path to coreutils echo to fix parallel --max-line-length-allowed.

Author: Bjørn Forsman

diff --git a/src/parallel b/src/parallel
index a047fd94..9fc5f671 100755
--- a/src/parallel
+++ b/src/parallel
@@ -11580,7 +11580,7 @@ sub is_acceptable_command_line_length($$) {
 	$len += length $Global::parallel_env;
     }
     # Force using non-built-in command
-    ::qqx("/bin/echo ".${string}x(($len-length "/bin/echo ")/length $string));
+    ::qqx("@coreutils@/bin/echo ".${string}x(($len-length "@coreutils@/bin/echo ")/length $string));
     ::debug("init", "$len=$? ");
     return not $?;
 }