9src/cc: pcc produces $O.out, keeps .6 objects; use basename for prog…

[staalmannen]

… detection

• Use basename of argv[0] (strip path prefix) so /amd64/bin/ape/pcc is detected as "pcc" correctly
• pcc output: smprint("%s.out", ot->o) e.g. "6.out" — matches Plan9 6l default and what mkmany expects
• pcc keeps .6 object files after linking (Plan9 native convention); only cc mode removes the intermediate .o (APE configure-compat mode)

https://claude.ai/code/session_01WGAwvvTwDg2yknFkmZ3qzs

[gemini-code-assist]

Code Review

This pull request modifies the compiler wrapper to distinguish between POSIX mode (cc) and Plan 9 native mode (pcc) by inspecting the program name. It adjusts the default output filename and object extension accordingly, and restricts intermediate file cleanup to POSIX mode. Review feedback identifies a potential null pointer dereference if the argument list is empty and suggests consolidating redundant string comparisons while adding necessary error handling for memory allocation in the pcc mode path.

[gemini-code-assist]

If argc is 0, argv[0] will be NULL, causing utfrrune to dereference a null pointer and crash. While argc is usually at least 1 in standard execution environments, adding a check for argv[0] or argc before processing the program name is a safer practice to ensure robustness.

[gemini-code-assist]

The strcmp(prog, "cc") check is performed twice. Consolidating this into an if-else block would improve readability and avoid redundant string comparisons. Additionally, smprint can return NULL if memory allocation fails; its return value should be checked to prevent a potential null pointer dereference later when oname is used.

	if(strcmp(prog, "cc") == 0){
		objext = "o";
		oname = "a.out";
	}else{
		objext = ot->o;
		if((oname = smprint("%s.out", ot->o)) == NULL){
			fprint(2, "out of memory\n");
			exits("mem");
		}
	}