Handle constant typedef global declaration (#878)

Author: kant2002

Cesium.CodeGen.Tests/CodeGenDeclarationsTests.cs

@@ -37,4 +37,10 @@ public Task StaticDeclarationsFuncionAndGlobalContext() => DoTest(
 
     static int i = 2;
 ");
+
+    [Fact]
+    public Task ConstTypeDef() => DoTest(
+        @"
+typedef int myint;
+static const myint i = 0;");
 }

Cesium.CodeGen.Tests/verified/CodeGenDeclarationsTests.ConstTypeDef.verified.txt

@@ -0,0 +1,4 @@
+System.Void <Module>::.cctor()
+  IL_0000: ldc.i4.0
+  IL_0001: stsfld System.Int32 testInput<Statics>::i
+  IL_0006: ret

Cesium.CodeGen/Extensions/TranslationUnitEx.cs

@@ -70,9 +70,10 @@ private static IEnumerable<IBlockItem> GetTopLevelDeclarations(SymbolDeclaration
                             throw new CompilationException($"CLI initializer should be a function for identifier {identifier}.");
                         }
 
-                        if (type is PrimitiveType or PointerType or InPlaceArrayType
-                            || (type is StructType varStructType && varStructType.Identifier != identifier)
-                            || type is NamedType)
+                        var nonConstType = type.EraseConstType();
+                        if (nonConstType is PrimitiveType or PointerType or InPlaceArrayType
+                            || (nonConstType is StructType varStructType && varStructType.Identifier != identifier)
+                            || nonConstType is NamedType)
                         {
                             var variable = new DeclarationBlockItem(new(storageClass, new(type, identifier, null), initializer));
                             yield return variable;