Unable to compile "gprolog.h" under Mac OS X/Project Builder

I have gprolog-1.2.13 compiled and running on my eMac, which runs OS X 
(10.1.5).  It runs Prolog programs fine but when I try and compile a C 
program that includes "gprolog.h", I get compiler warnings.

error: 	illegal external declaration, missing ; after 'reg_bank"
for line 221 in gprolog.h
	register WamWord 		*reg_bank asm ("15");

and

error:	illegal external declaration, missing ; after TR
for line 222 in gprolog.h
	register WamWordP		TR  asm ("20");


I'm not sure what the programmer was trying to accomplish with the "asm" 
statements.  Putting a semicolon in doesn't help either.  The Project 
Builder application is using the GCC 2.95.2 toolchain.

Thanks,

Phillip Soltan