Use C++17 to compile kdev-php
KDevelop uses this standard since https://commits.kde.org/kdevelop/f2925b5c6dc258def26c5f6d6d11433f896452c1
Its plugins must follow suit or they won't compile once C++17 features make it into kdevplatform headers.
KDevelop uses this standard since https://commits.kde.org/kdevelop/f2925b5c6dc258def26c5f6d6d11433f896452c1
Its plugins must follow suit or they won't compile once C++17 features make it into kdevplatform headers.