The former was deprecated with C++14.

According to the C++11 and C++17 standards, both files are identical.
Signed-off-by: Rosen Penev <rosenp@gmail.com>

This eliminates some overhead, because the compiler doesn't need to
consider these functions throwing.

Replaces g_ascii_strup() and allows building the Vorbis encoder
without GLib.

The null byte is whitespace, too.

Replaces g_str_has_suffix().

Replaces g_strstrip().

Replaces GLib's g_str_has_prefix().

Replaces GLib's g_ascii_strcasecmp().

Overload the name.

Eliminate the fallback strndup() and strnlen() implementations.

Usually, when strndup() is not available, strndup() isn't either,
because both are POSIX 2008.

This patch also adds extern "C" { } wrapper around string_util.h
to allow its usage in C++ code

Replace g_strchug() calls with a cheaper implementation.