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, 1 insertions, 1 deletions

diff --git a/lang/qt/src/dn.cpp b/lang/qt/src/dn.cpp
index d122333d..e41d481c 100644
--- a/lang/qt/src/dn.cpp
+++ b/lang/qt/src/dn.cpp
@@ -256,7 +256,7 @@ parse_dn(const unsigned char *string)
             break;    /* ready */
         }
 
-        DnPair pair = { 0, 0 };
+        DnPair pair = { nullptr, nullptr };
         string = parse_dn_part(&pair, string);
         if (!string) {
             goto failure;