uniq: support -w. closes bug 3094.

function                                             old     new   delta
packed_usage                                       24136   24132      -4
uniq_main                                            399     384     -15

testsuite/uniq.tests

@@ -41,6 +41,7 @@ testing "uniq input - (specify stdout)" "uniq input -" \
 #-c occurrences
 #-d dups only
 #-u
+#-w max chars
 
 # Test various command line options
 
@@ -60,6 +61,22 @@ aa	bb	cc9
 bb	cc	dd8
 aa	bb	cc9
 "
+testing "uniq -w (compare max characters)" "uniq -w 2" \
+"cc1
+" "" \
+"cc1
+cc2
+cc3
+"
+
+testing "uniq -s -w (skip fields and compare max chars)" \
+"uniq -s 2 -w 2" \
+"aaccaa
+" "" \
+"aaccaa
+aaccbb
+bbccaa
+"
 
 # -d is "Suppress the writing fo lines that are not repeated in the input."
 # -u is "Suppress the writing of lines that are repeated in the input."