compiler: Move and modernize

compiler is blitzcc, what I previously called compiler is now compiler_lib

compiler/lib/ex.hpp

@@ -0,0 +1,10 @@
+#pragma once
+#include <string>
+
+struct BlitzException {
+	std::string ex;  //what happened
+	int    pos; //source offset
+	std::string file;
+	BlitzException(const std::string& ex) : ex(ex), pos(-1) {}
+	BlitzException(const std::string& ex, int pos, const std::string& t) : ex(ex), pos(pos), file(t) {}
+};