recomp.c: output given warning in only one pass

Otherwise, it will be output multiple times.  This warning was untested
for as well.

1 files changed, 1 insertions, 1 deletions

diff --git a/regcomp.c b/regcomp.c
index 08b267bf8d..1730724dc1 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -10901,7 +10901,7 @@ S_grok_bslash_N(pTHX_ RExC_state_t *pRExC_state, regnode** node_p,
                 RExC_parse = endbrace;
                 vFAIL("\\N{} in character class restricted to one character");
             }
-            else {
+            else if (PASS2) {
                 ckWARNreg(endchar, "Using just the first character returned by \\N{} in character class");
             }
         }