GDK 3 update reassigns many core base types to libgdk

[Jeff Johnson]

A number of core types were reassigned by the GDK 3 data import to the GDK
library. Some examples:

 (0,0,'Const','const char','libgdk-3');
 (0,0,'Pointer','const char *','libgdk-3');
 (0,0,'Const','const int','libgdk-3');
 (0,0,'Pointer','const int *','libgdk-3');
 (0,0,'Const','const unsigned char','libgdk-3');
 (0,0,'Pointer','const unsigned char *','libgdk-3');
 (0,0,'Pointer','void *','libgdk-3');
 (0,0,'Pointer','void **','libgdk-3');
 (0,0,'Pointer','char *','libgdk-3');

(Not an exhaustive list!)

Those need to be assigned back where they were.

Additionally, we should check why libtodb2/headertodb2 wanted to do this, and
fix that issue so we don't have it in the future.