$OpenBSD: patch-Completion_Unix_Type__diff_options,v 1.2 2014/04/17 12:12:20 jasper Exp $
--- Completion/Unix/Type/_diff_options.orig	Wed Nov 27 20:00:19 2013
+++ Completion/Unix/Type/_diff_options	Mon Apr 14 18:10:09 2014
@@ -119,9 +119,35 @@ else
         '-S+[set first file in comparison]:start with file:_files'
       )
     ;;
+    openbsd*)
+      args=(
+        '(-c -e -f -q -u -C -D -U)-n[produce an rcsdiff(1)-compatible diff]'
+        '(-c -e -f -n -u -C -D -U)-q[only print a line when the files differ; does not produce a list of changes]'
+        '(-c -e -f -n -q -C -D -U)-u[produce a unified diff with 3 lines of context]'
+        '(-c -e -f -n -q -u -D -U)-C+[produce a context diff]:number of lines of context'
+        '(-c -e -f -n -q -u -C -U)-D[produce a merged file with preprocessor directives]:preprocessor symbol'
+        '(-c -e -f -n -q -u -C -D)-U+[produce a unified diff with NUMBER lines of context]:number of lines of context'
+        '-a[treat all files as ASCII text]'
+        '-d[try to produce the smallest diff possible]'
+        '-I[ignore changes whose lines match the extended regular expression]:extended regular expression pattern'
+        '-i[ignore case]'
+        '-l[long output format (paginate with pr(1))]'
+        '-L[print a label instead of the file name and time]:label'
+        '-p[show characters from the last line before the context]'
+        '-t[expand tabs in output lines]'
+        '-T[consistently align tabs]'
+        '-w[like -b, but totally ignore whitespace]'
+        '-N[treat absent files in either directory as if they were empty]'
+        '-P[treat absent files in the second directory as if they were empty]'
+        '-s[report files that are the same]'
+        '-S[start a directory diff from a file name]:file name'
+        '-X[Exclude files and subdirectories whose basenames match lines in a file]:file name'
+        '-x[Exclude files and subdirectories whose basenames match a pattern]:pattern'
+      )
+    ;;
   esac
-  
-  _arguments "$args[@]" \
+
+  _arguments -s "$args[@]" \
     "(-e -f -u -n)-c[output a context diff]" \
     "(-c -f -u -n)-e[output an ed script]" \
     "(-c -e -u -n)-f[output a reversed ed script]" \
