the configure script checks whether $CC compiles with -OPT:Olimit=0. For IRIX 5.3's cc, for example, although it is not supported, it only gives a warning and compiles nonetheless:

cc -OPT:Olimit=0 c.c
cc: Warning: -OPT options are ignored

The configure script tests do not check for this, so they do use that option. It's not so much of a problem that we constantly get respective warnings while
compiling; what's more of a problem (and therefore I call it a bug) is that python's configure does not go on checking for other optimizations. Therefore, on IRIX 5.3 with cc the -Olimit=1500 option, which would be needed, is not being configured.

Suggestion: also check whether there's anything on stderr while compiling the test code, and if so, don't use that particular option. Assuming make uses some /bin/sh you might use cc -OPT:Olimit=0 c.c 2>&1 >/dev/null and check whether there's any output (or maybe there are more elegant solutions).