libmakepkg: .com needs to be handled as an extension for win32 executable

[nu774]

3077636 doesn't take care of the .com extension.
It's at least used by mpv (mpv uses both of mpv.exe and mpv.com).

[lazka]

Thanks, that's something we should consider when tackling #29

[nu774]

BTW, you should also note that this line:

if LANG=en_US.UTF-8 LC_ALL=C objdump -f "${binary}" | grep -Eq '^start address 0x(0000000[01])?00401[0-9a-e][0-9a-e]0'

catches only x86 exe but not x64 exe.
cf. https://learn.microsoft.com/en-us/cpp/build/reference/base-base-address?view=msvc-170