[core] fix compile error on Solaris (fixes #2959)
[core] fix compile error on Solaris (fixes #2959)

(thx pyhalov)

x-ref:
  "Release 1.4.54 does not compile on an Open Solaris clone"
  https://redmine.lighttpd.net/issues/2959

gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,gstrauss/lighttpd1.4,gstrauss/lighttpd1.4,lighttpd/lighttpd1.4,lighttpd/lighttpd1.4