Fix C++ warnings

Makefile

@@ -15,7 +15,9 @@ MODULE_big := pg_libphonenumber
 OBJS := $(patsubst %.cpp,%.o,$(cpp_files))
 
 # C flags
-PG_CPPFLAGS := -fPIC -std=c++11 -Isrc/ -I/usr/include
+PG_CPPFLAGS := -fPIC -std=gnu++14
+PG_CPPFLAGS += -Isrc/ -I/usr/include
+PG_CPPFLAGS += -Wall -Wextra
 ifeq ($(CONFIG),debug)
 	PG_CPPFLAGS += -g -Og
 else

src/pg_libphonenumber.cpp

@@ -96,6 +96,7 @@ extern "C" {
             }
         } catch(std::exception& e) {
             reportException(e);
+            PG_RETURN_NULL();
         }
     }
 
@@ -309,6 +310,7 @@ extern "C" {
             }
         } catch(std::exception& e) {
             reportException(e);
+            PG_RETURN_NULL();
         }
     }
 
@@ -322,6 +324,7 @@ extern "C" {
             PG_RETURN_INT32(number->country_code());
         } catch(std::exception& e) {
             reportException(e);
+            PG_RETURN_NULL();
         }
     }
 }

src/short_phone_number.cpp

@@ -6,7 +6,7 @@ using namespace i18n::phonenumbers;
 const PhoneNumberUtil* const PhoneNumberTooLongException::phoneUtil = PhoneNumberUtil::GetInstance();
 
 PhoneNumberTooLongException::PhoneNumberTooLongException(const PhoneNumber& number, const char* msg) :
-    _number(number), std::runtime_error(msg) {};
+    std::runtime_error(msg), _number(number) {};
 
 std::string PhoneNumberTooLongException::number_string() const {
     std::string formatted;