clocale is part of C++11.

In practical terms, gcc's libstdc++ comes with its own locale defines
when the libc does not have them.

Also reworked to be dependent on !ANDROID.
Signed-off-by: Rosen Penev <rosenp@gmail.com>

"DEFAULT" is a bad name - all it says is that it's the default value,
but it doesn't say what it means.  The name NOTICE mimics the syslog
level.

Switch to std:: functions. Changed the meson check. Works locally.
Signed-off-by: Rosen Penev <rosenp@gmail.com>

Documentation says the limit is 5, but it was really 10 (at least
since 2004).  But since MPD wants to promote using many small clients
idling around, and these clients consume only very few resources, it
seems reasonable to raise this limit's default value.

The former was deprecated with C++14. The standard says they are the same
with one exception:

The header<climits>defines all macros the same as the C standard library
header<limits.h>.

[Note:The types of the constants defined by macros in<climits>are not
required to match the types to which themacros refer.— end note]
Signed-off-by: Rosen Penev <rosenp@gmail.com>

By eliminating GetAnyClient(), we can have instances with no outputs
at all.

Supports suffixes such as "kB" and "MB".

This fixes use-after-free bug in SimpleDatabase::Close(), accessing
the `root` object which was already freed by the `catch` block in
Open().

By having the Database on the stack first, we can avoid calling
Close() on the failed-to-open Database from Instance's destructor.

Closes #482