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/keygenerationresult.cpp b/lang/cpp/src/keygenerationresult.cpp
index ebbb3b99..49342f42 100644
--- a/lang/cpp/src/keygenerationresult.cpp
+++ b/lang/cpp/src/keygenerationresult.cpp
@@ -50,7 +50,7 @@ public:
         if (res.fpr) {
             std::free(res.fpr);
         }
-        res.fpr = 0;
+        res.fpr = nullptr;
     }
 
     _gpgme_op_genkey_result res;
@@ -94,5 +94,5 @@ bool GpgME::KeyGenerationResult::isSubkeyGenerated() const
 
 const char *GpgME::KeyGenerationResult::fingerprint() const
 {
-    return d ? d->res.fpr : 0 ;
+    return d ? d->res.fpr : nullptr ;
 }