fix warnings (#648)

* fix unknown command line argument

* fix warnings settings for gcc

* fix -Wzero-as-null-pointer-constant

* revert CMakeLists.txt

src/CMakeLists.txt

@@ -101,13 +101,8 @@ target_compile_options(
            $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:
            -Wall
            -Wextra
-           -Wpedantic
            # additional warnings
            -Wformat-nonliteral
-           -Wctor-dtor-privacy
-           -Wduplicated-branches
-           -Wduplicated-cond
-           -Wzero-as-null-pointer-constant
            #-Wsign-conversion
            -Wcast-align
            -Wpointer-arith
@@ -116,7 +111,10 @@ target_compile_options(
            -Wno-unused-parameter
            -Wno-sign-compare
            -Wno-unknown-pragmas
-           -Wno-gnu-anonymous-struct
+           >
+           $<$<CXX_COMPILER_ID:MSVC>:
+           -Wduplicated-branches
+           -Wduplicated-cond
            >)
 
 target_link_options(