Ensure static IdStrings get prepopulated when initializing yosys

An alternative would be to call ensure_prepopulated() in various
IdString methods.

kernel/rtlil.h

@@ -217,8 +217,7 @@ struct RTLIL::IdString
 			return it->second;
 		}
 
-		if (global_id_index_.empty())
-			prepopulate();
+		ensure_prepopulated();
 
 		if (!p[0])
 			return 0;
@@ -457,6 +456,12 @@ struct RTLIL::IdString
 
 private:
 	static void prepopulate();
+
+public:
+	static void ensure_prepopulated() {
+		if (global_id_index_.empty())
+			prepopulate();
+	}
 };
 
 namespace hashlib {

kernel/yosys.cc

@@ -196,6 +196,8 @@ void yosys_setup()
 	already_setup = true;
 	already_shutdown = false;
 
+	IdString::ensure_prepopulated();
+
 #ifdef WITH_PYTHON
 	// With Python 3.12, calling PyImport_AppendInittab on an already
 	// initialized platform fails (such as when libyosys is imported