Miscellaneous compiler warning fixes:

- Unused arguments.
 - Missing `override` in declarations.
 - Wstrict-prototypes in objective C.

PiperOrigin-RevId: 499496063

objectivec/GPBUtilities_PackagePrivate.h

@@ -58,7 +58,7 @@ CF_EXTERN_C_BEGIN
 // These two are used to inject a runtime check for version mismatch into the
 // generated sources to make sure they are linked with a supporting runtime.
 void GPBCheckRuntimeVersionSupport(int32_t objcRuntimeVersion);
-GPB_INLINE void GPB_DEBUG_CHECK_RUNTIME_VERSIONS() {
+GPB_INLINE void GPB_DEBUG_CHECK_RUNTIME_VERSIONS(void) {
   // NOTE: By being inline here, this captures the value from the library's
   // headers at the time the generated code was compiled.
 #if defined(DEBUG) && DEBUG
@@ -69,7 +69,7 @@ GPB_INLINE void GPB_DEBUG_CHECK_RUNTIME_VERSIONS() {
 // Legacy version of the checks, remove when GOOGLE_PROTOBUF_OBJC_GEN_VERSION
 // goes away (see more info in GPBBootstrap.h).
 void GPBCheckRuntimeVersionInternal(int32_t version);
-GPB_INLINE void GPBDebugCheckRuntimeVersion() {
+GPB_INLINE void GPBDebugCheckRuntimeVersion(void) {
 #if defined(DEBUG) && DEBUG
   GPBCheckRuntimeVersionInternal(GOOGLE_PROTOBUF_OBJC_GEN_VERSION);
 #endif

src/google/protobuf/arena.h

@@ -426,7 +426,7 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
     }
 
     template <typename U>
-    static Arena* GetOwningArena(Rank1, const U* p) {
+    static Arena* GetOwningArena(Rank1, const U*) {
       return nullptr;
     }
 
@@ -456,7 +456,7 @@ class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
     }
 
     template <typename U>
-    static Arena* GetArenaForAllocation(Rank2, const U* p) {
+    static Arena* GetArenaForAllocation(Rank2, const U*) {
       return nullptr;
     }