zlibVersion() and zlibCompileFlags() are not used in the kernel and boot
blocks. Comment this dead code out rather than remove it, to make future
updates easier.

Index: sys/lib/libz/zutil.c
===================================================================
RCS file: /OpenBSD/src/sys/lib/libz/zutil.c,v
diff -u -p -u -p -r1.8 zutil.c
--- sys/lib/libz/zutil.c	19 Mar 2026 15:14:51 -0000	1.8
+++ sys/lib/libz/zutil.c	20 Sep 2026 16:47:44 -0000
@@ -25,6 +25,7 @@ z_const char * const z_errmsg[10] = {
 };
 
 
+#if 0
 const char * ZEXPORT zlibVersion(void) {
     return ZLIB_VERSION;
 }
@@ -120,6 +121,7 @@ uLong ZEXPORT zlibCompileFlags(void) {
 #endif
     return flags;
 }
+#endif
 
 #ifdef ZLIB_DEBUG
 #include <stdlib.h>