Fix build with Qt 5.14
Summary:
Trying to build kdevelop-pg-qt with Qt 5.14 results in an error:
.../kdev-pg/kdev-pg-regexp.cpp:44:23: error: redefinition of ‘struct std::hash<QBitArray>’ template<> struct hash< type > \ ^~~~~~~~~~~~ .../kdev-pg/kdev-pg-regexp.cpp:53:1: note: in expansion of macro ‘q_Hash_to_tr1_hash’ q_Hash_to_tr1_hash(QBitArray) ^~~~~~~~~~~~~~~~~~ In file included from .../prefix514/include/QtCore/qvector.h:47:0, from .../prefix514/include/QtCore/QVector:1, from .../kdevelop-pg-qt/include/kdev-pg-char-sets.h:36, from .../kdevelop-pg-qt/kdev-pg/kdev-pg-regexp.cpp:20: .../prefix514/include/QtCore/qhashfunctions.h:209:1: note: previous definition of ‘struct std::hash<QBitArray>’ QT_SPECIALIZE_STD_HASH_TO_CALL_QHASH_BY_CREF(QBitArray) ^
std::hash<QBitArray> is already specialized in Qt 5.14, so avoid redefinition with conditional compilation
Test Plan: try to build with Qt 5.14
Reviewers: apol
Reviewed By: apol
Subscribers: kdevelop-devel
Tags: KDevelop
Differential Revision: https://phabricator.kde.org/D24914