qt,cpp: Consistently use nullptr and override

* lang/cpp/src/Makefile.am, lang/qt/src/Makefile.am (AM_CPPFLAGS):
Add suggest-override and zero-as-null-pointer-constant warnings.

* lang/cpp/src/*, lang/qt/src/*: Consistenly use nullptr and override.

--
This was especially important for the headers so that downstream
users of GpgME++ or QGpgME do not get flooded by warnings if
they have these warnings enabled.

It also improves compiler errors/warnings in case of accidental
mistakes.

1 files changed, 2 insertions, 2 deletions

diff --git a/lang/cpp/src/context_vanilla.cpp b/lang/cpp/src/context_vanilla.cpp
index 60ddea20..1d7d14d5 100644
--- a/lang/cpp/src/context_vanilla.cpp
+++ b/lang/cpp/src/context_vanilla.cpp
@@ -30,10 +30,10 @@
 
 GIOChannel *GpgME::getGIOChannel(int)
 {
-    return 0;
+    return nullptr;
 }
 
 QIODevice *GpgME::getQIODevice(int)
 {
-    return 0;
+    return nullptr;
 }