Merge DMD r317: bugzilla 3611 Enum forward referencing regression

---
 dmd/enum.c  |   17 +++++++++++++++--
 dmd/mtype.c |    4 ++++
 2 files changed, 19 insertions(+), 2 deletions(-)

dmd/enum.c

@@ -57,10 +57,23 @@ void EnumDeclaration::semantic(Scope *sc)
     Scope *sce;
 
     //printf("EnumDeclaration::semantic(sd = %p, '%s')\n", sc->scopesym, sc->scopesym->toChars());
-    if (symtab)			// if already done
-	return;
     if (!memtype)
 	memtype = Type::tint32;
+
+    if (symtab)			// if already done
+    {	if (!scope)
+	    return;		// semantic() already completed
+    }
+    else
+	symtab = new DsymbolTable();
+
+    Scope *scx = NULL;
+    if (scope)
+    {   sc = scope;
+        scx = scope;            // save so we don't make redundant copies
+        scope = NULL;
+    }
+
     if (sc->stc & STCdeprecated)
 	isdeprecated = 1;
 

dmd/mtype.c

@@ -4065,6 +4065,10 @@ Dsymbol *TypeEnum::toDsymbol(Scope *sc)
 
 Type *TypeEnum::toBasetype()
 {
+    if (sym->scope)
+    {
+	sym->semantic(NULL);	// attempt to resolve forward reference
+    }
     if (!sym->memtype)
     {
 #ifdef DEBUG