Nix expr: add isFlake argument to shellHook

Author: SignalWalker

default.nix

@@ -186,9 +186,9 @@ in {
 		IDEs = {
 			kate = [ kate omnisharp-roslyn ];
 		};
-		shellHook = drv: ''
+		shellHook = isFlake: drv: ''
 			export BIZHAWKBUILD_HOME='${builtins.toString ./.}'
-			export BIZHAWK_HOME="$BIZHAWKBUILD_HOME/output/"
+			export BIZHAWK_HOME="${if isFlake then "$(pwd -P)" else "$BIZHAWKBUILD_HOME"}/output/"
 			ldLibPath='${lib.makeLibraryPath drv.buildInputs}' # for running tests
 			if [ -z "$LD_LIBRARY_PATH" ]; then
 				export LD_LIBRARY_PATH="$ldLibPath"

flake.nix

@@ -46,7 +46,7 @@
                 powershell
               ];
               inputsFrom = [ drv ];
-              shellHook = avail.shellHook drv;
+              shellHook = avail.shellHook true drv;
             };
         in
         {

shell.nix

@@ -25,7 +25,7 @@
 			++ lib.optionals useVSCode [] #TODO https://devblogs.microsoft.com/dotnet/csharp-dev-kit-now-generally-available/ https://learn.microsoft.com/en-us/training/modules/implement-visual-studio-code-debugging-tools/
 			;
 		inputsFrom = [ drv ];
-		shellHook = avail.shellHook drv;
+		shellHook = avail.shellHook false drv;
 	};
 	shells = lib.pipe avail [
 		(lib.mapAttrs (name: drv: if lib.hasPrefix "bizhawkAssemblies-" name then drv else drv.assemblies or null))