This reverts commit cd4e6504dfbdface00037625f0cedda511e6d839.

As suggested by Martin on release-team@kde.org, given that it breaks SC.

Summary:
In case a kcfg with arg="true" was used and singleton the static
instance method only accepted a QString config name. This made it
impossible to combine a singleton config with an already existing and
open KSharedConfig::Ptr.

With this change an overloaded instance method is added which takes a
KSharedConfig::Ptr as argument. The private ctor, though, only takes a
KSharedConfig::Ptr and the instance method taking a QString argument
uses KSharedConfig::openConfig on the config file name.

This provides full API compatibility and at the same time allows to use
KSharedConfig in addition to the arg name based variant.

Test Plan:
kconfigcompiler tests still pass and a config with singleton
and arg="true" generates the code as I need it

Reviewers: #frameworks

Differential Revision: https://phabricator.kde.org/D3386

Summary: use qEnvironmentVariableIsSet instead of qgetenv().isEmpty()

Reviewers: #frameworks, sebas, sitter

Reviewed By: sebas, sitter

Differential Revision: https://phabricator.kde.org/D3314

REVIEW: 129382

REVIEW: 129188

REVIEW: 128608
CHANGELOG: Add Donate entry to KStandardShortcut

REVIEW: 128517