Sample of a subclass of ExecCommand that allows arbitrary build options

CustomC.sublime-build

{
    "target": "my_exec",

    "shell_cmd": "g++ \"${file}\" -o \"${file_path}/${file_base_name}\"",
    "file_regex": "^(..[^:]*):([0-9]+):?([0-9]+)?:? (.*)$",
    "working_dir": "${file_path}",
    "selector": "source.c, source.c++",

    "exe_path": "something.exe",
    "variants":
    [
        {
            "name": "Run",
            "shell_cmd": "g++ \"${file}\" -o \"${file_path}/${file_base_name}\" && \"${file_path}/${file_base_name}\""
        }
    ]
}

my_exec.py

import sublime
import sublime_plugin

from Default.exec import ExecCommand

class MyExecCommand(ExecCommand):
    def run(self, **kwargs):
        # All arguments that the exec command doesn't handle by default need
        # to be popped before continuing, since they're passed to the underlying
        # AsyncProcess, which will throw an error if it gets an unrecognized
        # argument.
        self.exe_path = kwargs.pop("exe_path", "")
        super().run(**kwargs)

    def finish(self, proc):
        super().finish(proc)

        print("The build is finished and exe_path is %s" % self.exe_path)