merge: fix coverity defects

 * coverity: strfcpy
 * coverity: add variable - function arg could be NULL/invalid
 * coverity: add variable - failed function leads to invalid variable
 * coverity: add variable - Context could become NULL
 * coverity: add variable - alloc/strdup could return NULL
 * coverity: add variable - route through code leads to invalid variable
 * coverity: remove variable test
 * coverity: test functions
 * coverity: tidy switches
 * coverity: unused variables
 * coverity: refactor only
 * coverity: check for buffer underruns
 * coverity: fix leaks
 * coverity: minor fixes