Compilation fails when C90 mode is enforced

[brainy]

I'm compiling utf8proc in strict C90 mode with -std=c90 -Werror=declaration-after-statement (never mind the reasons for that) and get the following error:

.../utf8proc.c:292:17: error: ISO C90 forbids mixing declarations and
      code [-Werror,-Wdeclaration-after-statement]
  utf8proc_bool break_permitted = grapheme_break_simple(lbc_override, tbc);