fixed a bunch of warnings from the Makefile from the root of the repo

Makefile

@@ -116,6 +116,7 @@ doctest:
 
 # calling Clang with all warnings, except:
 # -Wno-documentation-unknown-command: code uses user-defined commands like @complexity
+# -Wno-exit-time-destructors: warning in json code triggered by NLOHMANN_JSON_SERIALIZE_ENUM
 # -Wno-keyword-macro: unit-tests use "#define private public"
 # -Wno-deprecated-declarations: the library deprecated some functions
 # -Wno-weak-vtables: exception class is defined inline, but has virtual method
@@ -130,6 +131,7 @@ pedantic_clang:
 		-Werror \
 		-Weverything \
 		-Wno-documentation-unknown-command \
+        -Wno-exit-time-destructors \
 		-Wno-keyword-macro \
 		-Wno-deprecated-declarations \
 		-Wno-weak-vtables \