dmd -run fails with Nix on macOS Mojave

[Thomas Mader]

On Tuesday, 19 February 2019 at 21:06:29 UTC, Jonathan Marler 
wrote:
> On Tuesday, 19 February 2019 at 20:37:48 UTC, Thomas Mader 
> wrote:
>> On Tuesday, 19 February 2019 at 20:32:32 UTC, Thomas Mader 
>> wrote:
>>> I don't know what the compiler wants to write to 
>>> /var/tmp/dmd_runNVSCJp and why that fails with a Permission 
>>> denied.
>>
>> Ok I found it, it's created in link.d
>
> Not sure if macos does this, but on linux you can mount 
> directories as "noexec" which means you can't run executables 
> that live inside those mounts.  On linux you could check this 
> with "mount | grep /var/tmp", not sure if it's the same on 
> MacOS.
>
> (Related Issue: https://github.com/dragon-lang/rund/issues/17)

No that's not the problem.
Nix does not change mounts when a binary is run. All it's doing 
is specify it's own directories and this also includes the System 
Libs of macOS.
That's also the reason why official dmd package still works as 
all Nix stuff is contained in one directory and is only used by 
Nix executables.
Probably it's something with the C environment.
With this I could explain the thread error but the permission 
denied leaves me clueless because the directory is clearly 
writable.
I also already tried to patch link.d so P_tmpdir is not used 
anymore but a custom dir I defined but it did not change anything.