Many thanks for the message below which I found enlighetning. Seb. Russ Allbery (2023/09/11 11:23 -0700): > Nick Bowler <nbowler@xxxxxxxxxx> writes: > > > Looking at the code, CC is modified only if the -n32 option is needed to > > enable large-file support. The comments suggest this is required on > > IRIX. If large-file support can be enabled by preprocessor macros > > (which I imagine is the case on all current systems), AC_DEFINE is used. > > > It has been this way since the macro was originally added to Autoconf. > > I can only speculate as to why the original author used CC, but the > > reason is probably so that you can just take an existing package and > > just add AC_SYS_LARGEFILE with no other modifications and it will almost > > certainly work without any major problems. > > Back in the day when such flags were common (thankfully largely behind us > at this point), it was standard practice to put architecture selection > flags like -n32 into CC, not CFLAGS or CPPFLAGS. That's because such > flags are really of a different type than CFLAGS or CPPFLAGS, more akin to > invoking a different compiler for a different target architecture than the > normal uses of CFLAGS and CPPFLAGS. > > I suspect that the aswer to the original question is "don't worry about > it, just use AC_SYS_LARGEFILE, because no system you will build on will > need the CC modification anyway." >
