signed/unsigned needs to be at the beginning of a type

[rweichler]

For example, this:

ffi.cdef'long unsigned int x;'
ffi.cdef'long signed int x;'

Will error ';' expected near 'unsigned'

Seems like the bug is here:

cffi-lua/src/parser.cc

Line 2047 in 2621884

if (ls.t.token == TOK_signed || ls.t.token == TOK_unsigned) {