awk(1) segfaults when building kernel modules

`make -s buildkernel' seems to contain lots of segfaults after recent
update of one-true-awk in r224731. It chokes on sys/conf/kmod_syms.awk.
The case can be reduced to

  $ awk 'BEGIN { delete ARGV[1] } END { print ARGV[1] }' blah
  [...]
  Program received signal SIGSEGV, Segmentation fault.
  0x000000000040b778 in isclvar (s=0x0) at /usr/src/usr.bin/awk/../../contrib/one-true-awk/lib.c:674
  674             if (!isalpha((uschar) *s) && *s != '_')
  (gdb) bt
  #0  0x000000000040b778 in isclvar (s=0x0) at /usr/src/usr.bin/awk/../../contrib/one-true-awk/lib.c:674
  #1  0x00000000004092d7 in initgetrec () at /usr/src/usr.bin/awk/../../contrib/one-true-awk/lib.c:92
  #2  0x0000000000409397 in getrec (pbuf=0x6267e0, pbufsize=0x6248a8, isrecord=1)
      at /usr/src/usr.bin/awk/../../contrib/one-true-awk/lib.c:113
  #3  0x000000000040cd73 in program (a=0x8010830e8, n=258) at /usr/src/usr.bin/awk/../../contrib/one-true-awk/run.c:193
  #4  0x000000000040cbd0 in execute (u=0x8010830d0) at /usr/src/usr.bin/awk/../../contrib/one-true-awk/run.c:162
  #5  0x000000000040caaa in run (a=0x8010830d0) at /usr/src/usr.bin/awk/../../contrib/one-true-awk/run.c:137
  #6  0x000000000040bf85 in main (argc=2, argv=0x7fffffffd290) at /usr/src/usr.bin/awk/../../contrib/one-true-awk/main.c:183

Anyone else?