blueprint-compiler: wrap with required dependencies

without this, `blueprint-compiler` fails when trying to import GIR files
required by the compiler itself -- even for basic commands like
`blueprint-compiler --help` or `blueprint-compiler --version`.

`passthru.tests.version` passes because blueprint-compiler propagates
`gobject-introspection`, which has a setup hook that configures
`GI_TYPELIB_PATH` to have the required GIR files. but setup hooks are
only run within nix builds, and conditional on the hook being in
`nativeBuildInputs`. the result is that the following previously
_didn't_ work:

```
$ nix-build -A blueprint-compiler
$ ./result/bin/blueprint-compiler --help
```

an additional consequence of this patch is that several consumers of
blueprint-compiler now cross compile correctly:
- blanket
- komikku
- ...

previously, blueprint-compiler did not work in a cross compiling
environment, because the gobject-introspection setup-hook configures
GI_TYPELIB_PATH for the _host_, which is generally not the same host on
which blueprint-compiler is being run (i.e. the build machine).
a consumer of blueprint-compiler has (in effect) build inputs like:
```
nativeBuildInputs     | buildInputs
-----------------------------------
blueprint-compiler    |
gobject-introspection |
                      | glib
                      | gtk
                      | adwaita
...                   | ...
```

gobject-introspection's setup-hook populates GI_TYPELIB_PATH from the
buildInputs; this is correct when blueprint-compiler is querying
typelibs to generate code against, however before it gets to that
point it needs to import its _own_ typelib dependencies (glib and
gobject-introspection). this is made possible by wrapGAppsNoGuiHook,
which wraps blueprint-compiler with a copy of those typelibs built
for the same platform as it.

pkgs/by-name/bl/blueprint-compiler/package.nix

@@ -7,8 +7,10 @@
   meson,
   ninja,
   python3,
+  runCommand,
   stdenv,
   testers,
+  wrapGAppsNoGuiHook,
   xvfb-run,
 }:
 stdenv.mkDerivation (finalAttrs: {
@@ -30,6 +32,7 @@ stdenv.mkDerivation (finalAttrs: {
   nativeBuildInputs = [
     meson
     ninja
+    wrapGAppsNoGuiHook
   ];
 
   buildInputs = [
@@ -64,9 +67,18 @@ stdenv.mkDerivation (finalAttrs: {
     runHook postCheck
   '';
 
-  passthru.tests.version = testers.testVersion {
+  passthru.tests = {
+    version = testers.testVersion {
       package = finalAttrs.finalPackage;
     };
+    # regression test that `blueprint-compiler` can be used in a standalone
+    # context outside of nix builds, and doesn't rely on the setup hooks of
+    # its propagated inputs for basic functionality.
+    # see https://github.com/NixOS/nixpkgs/pull/400415
+    standalone = runCommand "blueprint-compiler-test-standalone" { } ''
+      ${lib.getExe finalAttrs.finalPackage} --help && touch $out
+    '';
+  };
 
   meta = with lib; {
     description = "Markup language for GTK user interface files";