cflashy: macos compatibility

[petemoore]

It seems that macOS supports fewer serial baud rates than Linux, and so the incompatible baud rates have been removed when compiling under macOS.

pmoore@Peters-MacBook-Pro-2:~/git/circle fix-cflashy-macos $ cat /Library/Developer/CommandLineTools/SDKs/MacOSX14.4.sdk/usr/include/sys/termios.h | grep '#define B[0-9][0-9]*' | sort -n -k3
#define B0      0
#define B50     50
#define B75     75
#define B110    110
#define B134    134
#define B150    150
#define B200    200
#define B300    300
#define B600    600
#define B1200   1200
#define B1800   1800
#define B2400   2400
#define B4800   4800
#define B7200   7200
#define B9600   9600
#define B14400  14400
#define B19200  19200
#define B28800  28800
#define B38400  38400
#define B57600  57600
#define B76800  76800
#define B115200 115200
#define B230400 230400

I've only tested that this fixes the compilation. I have not tested the compiled binary, please let me know if that is required. Many thanks Rene!

Originally raised in #499.

[rsta2]

That's a better solution. Thanks! I don't know, if you have an USB-to-serial adapter, which can be connected between your Mac and RPi? That would be required for a test. Otherwise I would merge the PR without a bootloader test, because it's already an improvement.

[petemoore]

I'm on a trip with just my laptop for the next couple of weeks, so feel free to merge, thanks Rene! I'm happy to also test it when I am back in Germany.

[rsta2]

OK, no problem. Have a nice trip, Pete!