Alignment warnings when casting char* pointers

[jphickey]

Describe the bug
When compiling on architectures with strict alignment requirements, casts between char* (as used in some pointer arithmetic to calculate addresses) to other types triggers a warning about alignment.

To Reproduce
Build for an architecture with strict alignment requirements (SPARC, MIPS, etc).
Example compiler warning:

/home/joe/code/cfecfs/github/cfe/fsw/cfe-core/src/sb/cfe_sb_buf.c:119:30: warning: cast increases required alignment of target type [-Wcast-align]
    CFE_SB_BufferD_t    *bd = (CFE_SB_BufferD_t *)(((uint8 *)Address) - sizeof(CFE_SB_BufferD_t));

Expected behavior
Should build cleanly with no warnings

System observed on:

• Ubuntu 18.04 LTS build host
• MIPS cross compiler (mips-poky-linux-gcc version 8.2.0)

Additional context
Many of these are actually safe because CFE ensures that the sizeof(CFE_SB_BufferD_t) as well as the base/pool addresses are aligned for the largest data types. However, because the pointer arithmetic is done as a unsigned char* the compiler sees the cast from an unsigned char* to a larger type as an issue.

Reporter Info
Joseph Hickey, Vantage Systems, Inc.