Split Q_COMPILER_UNICODE_STRINGS: add Q_STDLIB_UNICODE_STRINGS

Since commit bf2160e72cd8840a8e604438cbdc807483ac980a, we can rely on
charNN_t support in all compilers except MSVC 2013, and since that
commit, we use (in 5.10, not 5.9, yet)

  !defined(Q_OS_WIN) || defined(Q_COMPILER_UNICODE_STRINGS)

when we only need charNN_t, the type, as opposed to its library
support (u16string, char_traits<char16_t>, ...).

This patch splits the Q_C_UNICODE_STRINGS macro into two, adding
Q_STDLIB_UNICODE_STRINGS for when we need std::uNNstring, leaving
Q_C_UNICODE_STRINGS for when we need just charNN_t support.

In QDebug, when constructing a QChar out of a char16_t, cast to ushort
first, since QChar(char16_t) was only officially introduced in Qt 5.10.

[ChangeLog][Potentially Source-Incompatible Changes] The internal
Q_COMPILER_UNICODE_STRINGS macro is now defined if the compiler
supports charNN_t, even if the standard library does not. To check for
availability of std::uNNstring, use the new Q_STDLIB_UNICODE_STRINGS
macro.

Change-Id: I8f210fd7f1799fe21faf54506475a759b1f76a59
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

0 files changed, 0 insertions, 0 deletions