I managed to get version 1.2-2.7.2 compiled on both, but neither works very well. On Solaris gpc1 gets a fatal signal, and an internal compiler error, when compiling certain programs. On SunOS, it seems to compile properly, but it dumps core when linking.
Yes, I have gpc 1.2 (2.7.2) compiled and running under both SunOS and Solaris. It is true that there are still some bugs in gpc that allow gpc1 to core dump. Those should be reported. Several of my "standard" programs compile and run with no problem. In fact, we have had our students using gpc as their primary PASCAL compiler for a couple of years.