Use C++17 to compile Umbrello
KDevelop uses this standard since https://commits.kde.org/kdevelop/f2925b5c6dc258def26c5f6d6d11433f896452c1
Umbrello depends on KDevelop Platform and so must follow suit. Without this change Umbrello does not compile against the current kdevplatform master version.
Increase the required CMake version to 3.8, because the CXX_STANDARD
property started supporting the value "17
" in this version.
Testing done: Umbrello compiles with and without kdev-php plugin installed. All 13 tests pass.
Edited by Igor Kushnir