Why is Premake5 not creating the necessary output directories for my project?

Question

I'm using Premake5 as my build system for a C project on Windows. I'm using three scripts for my project:

• premake5.lua

workspace "epoch"
    configurations { "Debug", "Release", "Dist" }
    architecture "x86_64"
    startproject "sandbox"

include "runtime/runtime.lua"
include "sandbox/sandbox.lua"

• runtime/runtime.lua

project "runtime"
    kind "SharedLib"
    language "C"

    targetdir "../bin/%{cfg.buildcfg}"
    objdir "../obj/%{cfg.buildcfg}"

    files {
        "runtime/src/**.c",
        "runtime/src/**.h"
    }

    filter "configurations:Debug"
        symbols "On"

    filter "configurations:Release or configurations:Dist"
        optimize "On"

• sandbox/sandbox.lua

project "sandbox"
    kind "WindowedApp"
    language "C"

    targetdir "../bin/%{cfg.buildcfg}"
    objdir "../obj/%{cfg.buildcfg}"

    files {
        "sandbox/src/**.c",
        "sandbox/src/**.h"
    }

    filter "configurations:Debug"
        symbols "On"

    filter "configurations:Release or configurations:Dist"
        optimize "On"

I;m using the gmake2 generator, but when I call make on the resulting Makefile, I get the following error:

==== Building runtime (debug) ====
Creating ../bin/Debug
mkdir: cannot create directory '..\\bin\\Debug': No such file or directory
make[1]: *** [Makefile:88: ../bin/Debug] Error 1
make: *** [Makefile:36: runtime] Error 2

My understanding is that this is due to the bin directory not existing prior to the mkdir call. How can I fix this?