Enable more C++ compiler warnings

libsolidity/analysis/GlobalContext.cpp

@@ -34,6 +34,8 @@ using namespace std;
 namespace solidity::frontend
 {
 
+namespace
+{
 /// Magic variables get negative ids for easy differentiation
 int magicVariableToID(std::string const& _name)
 {
@@ -113,6 +115,8 @@ inline vector<shared_ptr<MagicVariableDeclaration const>> constructMagicVariable
 	};
 }
 
+}
+
 GlobalContext::GlobalContext(): m_magicVariables{constructMagicVariables()}
 {
 }