Only fill total_size in CheckBufferOverrun::checkFunctionParameter when it's useful.
Fixed #5874 (False positive: 'opposite conditions in nested if' with arrays)
Merge pull request #327 from simartin/only_fill_if_needed

Only fill total_size in CheckBufferOverrun::checkFunctionParameter when useful
Fixed #5857 (strPlusChar: Crash on invalid code 'int+;')
travis: replace kernel check with clang check.

Check clang instead of kernel, which is a lot faster.
Make clang check failure fatal to the build.
travis: run test_matchcompiler.py
travis: move CHECK_INTERNAL check up, remove "SRCDIR=build VERIFY=1" job in favor of "MAKEFLAGS="HAVE_RULES=yes" SRCDIR=build VERIFY=1"
travis: add -DCHECK_INTERNAL to the VERIFY=1 job to automatically fetch issues like #5869 via travis