compiler, testing: Build System for Compilation

The compilation code was written as a precursor for implementation
with macros. The updates in this commit make the switch.

There is still plenty to do:

1. Comment Walker.
2. Comment Macros.

Signed-off-by: Will Hawkins <hawkinsw@obs.cr>

Sources/P4Lang/Declarations.swift

@@ -64,7 +64,6 @@ public struct FunctionDeclaration: P4DataType, P4DataValue {
   }
 
   public func eq(rhs: any Common.P4DataType) -> Bool {
-    print("Checking a type: me: \(self) vs them: \(rhs)!")
     switch rhs {
     case let frhs as FunctionDeclaration:
       return frhs.tipe.eq(self.tipe) && frhs.params == self.params