fix: fix @mtkbuild macro keyword parsing

Author: AayushSabharwal

src/systems/abstractsystem.jl

@@ -2248,15 +2248,20 @@ macro mtkbuild(exprs...)
     expr = exprs[1]
     named_expr = ModelingToolkit.named_expr(expr)
     name = named_expr.args[1]
-    kwargs = if length(exprs) > 1
-        NamedTuple{Tuple(ex.args[1] for ex in Base.tail(exprs))}(Tuple(ex.args[2]
-        for ex in Base.tail(exprs)))
+    kwargs = Base.tail(exprs)
+    kwargs = map(kwargs) do ex
+        @assert ex.head == :(=)
+        Expr(:kw, ex.args[1], ex.args[2])
+    end
+    if isempty(kwargs)
+        kwargs = ()
     else
-        (;)
+        kwargs = (Expr(:parameters, kwargs...),)
     end
+    call_expr = Expr(:call, structural_simplify, kwargs..., name)
     esc(quote
         $named_expr
-        $name = $structural_simplify($name; $(kwargs)...)
+        $name = $call_expr
     end)
 end
 

test/if_lifting.jl

@@ -110,3 +110,17 @@ end
         @test operation(eq.rhs) === ifelse
     end
 end
+
+@testset "`@mtkbuild` macro accepts `additional_passes`" begin
+    @mtkmodel SimpleAbs begin
+        @variables begin
+            x(t)
+            y(t)
+        end
+        @equations begin
+            D(x) ~ abs(y)
+            y ~ sin(t)
+        end
+    end
+    @test_nowarn @mtkbuild sys=SimpleAbs() additional_passes=[IfLifting]
+end