musl: backport reallocarray and others.

It's in POSIX-future and some applications have started depending on it.
It's easier to backport into musl than fix each individual package.

Since we are adding a new interface to libc, update common/shlibs entry
as well. This should probably have been done for all musl updates.

And since we are here, also backport:
- isascii fix (removes the need for a patch in fceux)
- make epoll a cancellation point (fixes a bug in jack pipewire utilities)

common/shlibs

@@ -16,7 +16,7 @@
 # PLEASE NOTE: when multiple packages provide the same SONAME, the first
 # one (order top->bottom) is preferred over the next ones.
 #
-libc.so musl-1.1.21_1
+libc.so musl-1.1.24_7
 libc.so.6 glibc-2.32_1
 libm.so.6 glibc-2.32_1
 libpthread.so.0 glibc-2.32_1