>
> or did you run it from inside another Emacs session?


No.

Also, does the same command succeed if you run it from the Bash
> command line?  Does it succeed if you run it from the cmd.exe command
> line?


No, has nothing to do with it.

I've got something amazing/phenomenal here. Read carefully. With "-g -O0"
it can reserve memory just fine and everything builds successfully. With
"-O3" it fails with the first try, i.e. with the size of 0x68000000 and the
corresponding error is:

ERROR_NOT_ENOUGH_MEMORY
> 8 (0x8)
> Not enough storage is available to process this command.


 Since with "-g -O0" it succeeds, it cannot be debugged with GDB. For "-O3"
I used simple `printf' testing.

 I can test "-O2" if you are interested.

What does it smell like? A toolchain bug?