Fails on installing pg gem about postgresql HOT 9 CLOSED

"gcc -o conftest -I/opt/chef/embedded/include/ruby-1.9.1/i686-linux -I/opt/chef/embedded/include/ruby-1.9.1/ruby/backward -I/opt/chef/embedded/include/ruby-1.9
.1 -I. -I/usr/include/postgresql  -D_FILE_OFFSET_BITS=64  -I/opt/chef/embedded/include -I/opt/chef/embedded/include -O3 -g -pipe -fPIC conftest.c  -L. -L/opt/c
hef/embedded/lib -Wl,-R/opt/chef/embedded/lib -L/usr/lib -Wl,-R/usr/lib -L/opt/chef/embedded/lib -Wl,-R/opt/chef/embedded/lib -L. -Wl,-rpath,/opt/chef/embedded
/lib -L/opt/chef/embedded/lib -rdynamic -Wl,-export-dynamic -L/opt/chef/embedded/lib  -Wl,-R/opt/chef/embedded/lib      -Wl,-R -Wl,/opt/chef/embedded/lib -L/op
t/chef/embedded/lib -lruby -lpq  -lpthread -lrt -ldl -lcrypt -lm   -lc"
conftest.c: In function ‘t’:
conftest.c:6:1: error: too few arguments to function ‘PQconnectdb’
/usr/include/postgresql/libpq-fe.h:243:16: note: declared here
checked program was:
/* begin */
 1: #include "ruby.h"
 2:
 3: #include <libpq-fe.h>
 4:
 5: /*top*/
 6: int t() { PQconnectdb(); return 0; }
 7: int main(int argc, char **argv)
 8: {
 9:   if (argc > 1000000) {
10:     printf("%p", &t);
11:   }
12:
13:   return 0;
14: }
/* end */