Interesting. Summer 84/85 (maybe 85/86) I used a port of PCC to System/360 (done, I believe, by Scott Kristjanson) on the University of British Columbia mainframes (Amdahls running MTS). I was working on mail software, so I had to deal with EBCDIC/ASCII issues, which was no fun.
I sometimes wonder if that compiler has survived anywhere.
z/OS 3.1 is certified for UNIX 95, if this list is correct:
https://www.opengroup.org/openbrand/register/index2.html
That would include a C compiler, but yours is probably on tape somewhere.
Linux has been on this list, courtesy of two Chinese companies.