select uuid_generate_v4()

#include <stdio.h>
#include <dlfcn.h>

int main()
{
        void * ptr = dlopen( "/usr/local/lib/postgresql/uuid-ossp.so",RTLD_NOW);
        if( ptr == NULL )
        {
                printf("%s\n",dlerror());
        }
}

create or replace function tools.uuid_generate_v4() returns uuid as
$$
  select array_to_string(
    array (
      select
        case when (( idx = 8 ) or ( idx = 13 ) or ( idx = 18 ) or ( idx = 23 )) then
          '-'
        else
          substring( '0123456789abcdef' from (( random() * 15 )::int + 1 ) for 1 )
        end
      from
        generate_series( 0, 35 ) idx
    ), ''
  )::uuid
$$
  LANGUAGE sql;