1 files changed, 4 insertions, 1 deletions

diff --git a/editors/diff.c b/editors/diff.c
index 0c75873b3..ef2030527 100644
--- a/editors/diff.c
+++ b/editors/diff.c
@@ -94,7 +94,7 @@ enum {                   /* Commandline flags */
         FLAG_a,
         FLAG_b,
         FLAG_d,
-        FLAG_i, /* unused */
+        FLAG_i,
         FLAG_L, /* unused */
         FLAG_N,
         FLAG_q,
@@ -177,6 +177,9 @@ static int read_token(FILE_and_pos_t *ft, token_t tok)
                 if (t == '\n')
                         tok |= TOK_EOL;
 
+                if (option_mask32 & FLAG(i)) /* Handcoded tolower() */
+                        t = (t >= 'A' && t <= 'Z') ? t - ('A' - 'a') : t;
+
                 if ((option_mask32 & FLAG(w)) && is_space)
                         continue;