musl: Upgrade to tip of trunk

musl: Upgrade to tip of trunk

Brings following changes

* 83b858f8 fix rejection of dns responses with pointers past 512 byte offset
* a4ecaf89 dns stub resolver: increase buffer size to handle chained CNAMEs
* 40834f6c printf core: fix gratuitous integer formatting buffer size
* 3a23cd06 all printf variants: fix argument type handling for %c and %lc
* fa4a8abd fix public clone function to be safe and usable by applications
* 0c277ff1 fix broken thread list unlocking after fork
* 4653b987 mbrtowc: Fix wrong return value when n > UINT_MAX
* b90841e2 configure: replace -Os with equivalent based on -O2

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>