dockerTools.buildImageWithNixDb: export USER
Changes to Nix user detection (./src/nix-channel/nix-channel.cc#L-166)
cause this function to error. Exporting USER fixes this.
Fixes this error:
gnuplot> plot [-5:5] sin(x)
qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in ""
This application failed to start because no Qt platform plugin could
be initialized. Reinstalling the application may fix this problem.
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Since 2.44_01, the behaviour for `check_lib` in their `Makefile.PL` has
been "fixed" to fail when the `assert_lib` function fails to build the
test.
* https://github.com/toddr/XML-Parser/commit/2bc1e90c04220a04a0b40d1047d464bc55f56210
Now, this wouldn't be so bad, since it's good to actually test what
stuff is being compiled against.
Except that *something* is wonky with the cross-compilation build-time
Perl.
```
Undefined subroutine &File::Temp::mktemp called at inc/Devel/CheckLib.pm line 236.
```
As far as I know, this is a built-in function from Perl.
* https://perldoc.perl.org/File/Temp.html
Though, something *else* is wrong with `Checklib.pm`. Side-stepping the
issue by (eww) shelling out to `mktemp`, we get these errors:
```
/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-armv7l-unknown-linux-gnueabihf-binutils-2.31.1/bin/armv7l-unknown-linux-gnueabihf-ld: assertlib_src1_0.553056903257133: file not recognized: file truncated
collect2: error: ld returned 1 exit status
-I/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-expat-2.2.8-armv7l-unknown-linux-gnueabihf-dev/include -L/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-expat-2.2.8-armv7l-unknown-linux-gnueabihf/lib -lexpat
/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-armv7l-unknown-linux-gnueabihf-binutils-2.31.1/bin/armv7l-unknown-linux-gnueabihf-ld: assertlib_src2_0.262169388446154: file not recognized: file truncated
collect2: error: ld returned 1 exit status
Can't link/include C library 'expat.h', 'expat', aborting.
```
Meanwhile, the actual build, while building the library, seemingly has
no issues building using those paths. `¯\_(ツ)_/¯`
Michael Raskin