Default to __cdecl for name mangling

It's definitely ideal for everything to be declared explicitly, but it
would require either manual intervention or a new dedicated script to do
this for typedefs (that aren't methods), so we'll do this as the least
worst option.

ghidra/ghidra_scripts/MSVC7Mangle.java

@@ -168,10 +168,7 @@ public class MSVC7Mangle extends GhidraScript {
 				f.getName() +
 				"(): __thiscall not allowed for C symbols"
 			);
-			default           -> throw new Exception(
-				f.getName() +
-				"(): Need to specify calling convention"
-			);
+			default           -> "_" + f.getName(false); // Default to __cdecl
 		};
 	}
 
@@ -400,10 +397,7 @@ public class MSVC7Mangle extends GhidraScript {
 			case "__thiscall" -> "E";
 			case "__fastcall" -> "I";
 			case "__stdcall"  -> "G";
-			default           -> throw new Exception(
-				f.getName() +
-				"(): Need to specify calling convention"
-			);
+			default           -> "A"; // Default to __cdecl
 		};
 	}