Typecast memcchr in os-shared-common.h

[thesamprice]

Describe the bug
memchr is called and then assigned to a const char * without a cast.
This causes failures on certain compilers (llvm).

https://www.cplusplus.com/reference/cstring/memchr/

const void * memchr ( const void * ptr, int value, size_t num );
      void * memchr (       void * ptr, int value, size_t num );

In file os-shared-common.h
change

    const char *end = memchr(s, 0, maxlen);

to

    const char *end = (const char *)memchr(s, 0, maxlen);

System observed on:

• Hardware
• OS: [MAC]
• Versions [OSAL Hash 7ebb463]

clang --version
Apple clang version 12.0.0 (clang-1200.0.32.29)
Target: x86_64-apple-darwin19.6.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

Reporter Info
Sam Price - GSFC