Compiling zsh 4.3.4 on OpenBSD, I get:

utils.c: In function `getkeystring':
utils.c:4746: error: `count' undeclared (first use in this function)
utils.c:4746: error: (Each undeclared identifier is reported only once
utils.c:4746: error: for each function it appears in.)

Having a look at the source utils.c, I suspect that `count' is really 
undeclared in case that 

- `HAVE_NL_LANGINFO' and `CODESET' are defined,
- and `HAVE_ICONV' is not defined,
- and one of the following is also not defined: `HAVE_WCHAR_H', 
  `HAVE_WCTOMB', `__STDC_ISO_10646__'.

Maybe this is a rare configuration that only occurs on OpenBSD.