Apply by doing:
       cd /usr/src/usr.sbin/kvm_mkdb
       patch < kvm_mkdb.patch

make && make install

Index: nlist.c
===================================================================
RCS file: /cvs/src/usr.sbin/kvm_mkdb/nlist.c,v
retrieving revision 1.14
retrieving revision 1.15
diff -u -r1.14 -r1.15
--- nlist.c     1998/09/26 07:16:23     1.14
+++ nlist.c     1998/10/28 23:20:01     1.15
@@ -96,7 +96,7 @@
       int nr, strsize;
       size_t len;
       u_long kerntextoff;
-       size_t snamesize;
+       size_t snamesize = 0;
       char *strtab, buf[1024], *sname, *p;

       /* Read in exec structure. */