ignore new clang warning security.insecureAPI.DeprecatedOrUnsafeBufferHandling

clang9.0.0 (https://releases.llvm.org/9.0.0/tools/clang/docs/ReleaseNotes.html)
adds a new satic analyzer: security.insecureAPI.DeprecatedOrUnsafeBufferHandling
which throws warnings if you use "unsafe" buffer handling functions which
includes memset and memcpy.
We have memset and mempy all over the place, so I think it's best to ignore this warning.
All the occurences that I looked at seemed perfectly "safe" to me.

.clang-tidy

@@ -1,5 +1,5 @@
 ---
-Checks:          '*,-llvm-header-guard,-hicpp-*,-readability-function-size,-google-readability-todo,-readability-magic-numbers,-cppcoreguidelines-avoid-magic-numbers,-readability-isolate-declaration,-readability-uppercase-literal-suffix'
+Checks:          '*,-llvm-header-guard,-hicpp-*,-readability-function-size,-google-readability-todo,-readability-magic-numbers,-cppcoreguidelines-avoid-magic-numbers,-readability-isolate-declaration,-readability-uppercase-literal-suffix,-clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling'
 WarningsAsErrors: '*'
 HeaderFilterRegex: '.*'
 AnalyzeTemporaryDtors: false