lgtm: enable more (and potentially useful) queries

Not all available queries on LGTM are enabled by default, but some of
the excluded ones might come in handy, hence let's enable them
explicitly.

.lgtm.yml

@@ -1,6 +1,27 @@
 ---
 # vi: ts=2 sw=2 et:
 
+# Explicitly enable certain checks which are hidden by default
+queries:
+  - include: cpp/bad-strncpy-size
+  - include: cpp/declaration-hides-variable
+  - include: cpp/inconsistent-null-check
+  - include: cpp/mistyped-function-arguments
+  - include: cpp/nested-loops-with-same-variable
+  - include: cpp/sizeof-side-effect
+  - include: cpp/suspicious-pointer-scaling
+  - include: cpp/suspicious-pointer-scaling-void
+  - include: cpp/suspicious-sizeof
+  - include: cpp/unsafe-strcat
+  - include: cpp/unsafe-strncat
+  - include: cpp/unsigned-difference-expression-compared-zero
+  - include: cpp/unused-local-variable
+  - include:
+      tags:
+        - "security"
+        - "correctness"
+      severity: "error"
+
 extraction:
   cpp:
     prepare: