honggfuzz.h: initialize input mutex
diff --git a/cmdline.c b/cmdline.c
index 44b9acc..fdff153 100644
--- a/cmdline.c
+++ b/cmdline.c
@@ -421,6 +421,7 @@
                 .dynfileq = PTHREAD_RWLOCK_INITIALIZER,
                 .feedback = PTHREAD_MUTEX_INITIALIZER,
                 .report   = PTHREAD_MUTEX_INITIALIZER,
+                .input    = PTHREAD_MUTEX_INITIALIZER,
             },
 
         /* Linux code */