clang 19 static analyzer run & clean-up

[sneakywumpus]

altairsim/srcsim/simcfg.c,
cpmsim/srcsim/simio.c,
cromemcosim/srcsim/simcfg.c,
imsaisim/srcsim/simcfg.c,
intelmdssim/srcsim/simcfg.c,
mosteksim/srcsim/simcfg.c:

Changed

        s = buf;
        while (fgets(s, BUFSIZE, ...)) {

to

        while (fget(buf, BUFSIZE, ...)) {
                s = buf;

since s was sometimes manipulated inside the loop.

cpmsim/srcsim/simmem.h:

Changed memrdr to match memwrt, no functional change. Analyzer complained about a useless assignment.

cpmsim/srctools/bin2hex.c,
cpmsim/srctools/mkdskimg.c,
frontpanel/jpeg.c:

Unclosed files, also reformatted bin2hex.c.

z80core/simmain.c:

Re-did save_core and load_core since the analyzer complained about unchecked errors.

iodevices/altair-88-dcdd.c:

Renamed dsk_check to dsk_open and leave file open on success. Analyzer complained about possible open(2) fail in altair_dsk_data_out and altair_dsk_data_in.

frontpanel/lpanel.c:

Fix possible memory leak.

Rest of files: Changed &buf[0] to buf, for strings and buffers, since this looks more natural in C.

[sneakywumpus]

The cpmsim/srcsim/simmem.h change is a fall-out of my hardware breakpoint changes.