Adopt Xcode recommended settings and fix resulting build errors

Applied Xcode's "Update to recommended settings" (new warning flags,
LastUpgradeCheck 2650, scheme bumps, Info.plist tidy-up), then fixed the
build failures those stricter checks surfaced:

- Disable ENABLE_MODULE_VERIFIER and CLANG_WARN_QUOTED_INCLUDE_IN_FRAMEWORK_HEADER:
  the library intentionally uses quoted includes so the flat include/
  symlink directory resolves them for SPM; the module verifier rejects
  that.
- Add (void) to the GCDWebServerInitializeFunctions and
  _ExecuteMainThreadRunLoopSources definitions (CLANG_WARN_STRICT_PROTOTYPES
  + -Werror).
- Cast both branches of the status-code ternary in
  GCDWebServerConnection to NSInteger (-Wenum-compare-conditional mixed
  two enum types).

Verified: Run-Tests.sh, swift build, and the Xcode framework build all pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Frameworks/Info.plist

@@ -7,16 +7,16 @@
 	<key>CFBundleExecutable</key>
 	<string>$(EXECUTABLE_NAME)</string>
 	<key>CFBundleIdentifier</key>
-	<string>${PRODUCT_BUNDLE_IDENTIFIER}</string>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
 	<key>CFBundleInfoDictionaryVersion</key>
 	<string>6.0</string>
 	<key>CFBundleName</key>
 	<string>$(PRODUCT_NAME)</string>
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
-	<key>CFBundleVersion</key>
-	<string>${BUNDLE_VERSION_STRING}</string>
 	<key>CFBundleShortVersionString</key>
 	<string>${BUNDLE_VERSION_STRING}</string>
+	<key>CFBundleVersion</key>
+	<string>${BUNDLE_VERSION_STRING}</string>
 </dict>
 </plist>

GCDWebServer.xcodeproj/project.pbxproj

@@ -838,7 +838,8 @@
 		08FB7793FE84155DC02AAC07 /* Project object */ = {
 			isa = PBXProject;
 			attributes = {
-				LastUpgradeCheck = 1130;
+				BuildIndependentTargetsInParallel = YES;
+				LastUpgradeCheck = 2650;
 				TargetAttributes = {
 					CEE28CD01AE004D800F4023C = {
 						CreatedOnToolsVersion = 6.3;
@@ -1146,6 +1147,7 @@
 		1DEB928608733DD80010E9CD /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				DEAD_CODE_STRIPPING = YES;
 				MACOSX_DEPLOYMENT_TARGET = 12;
 				PRODUCT_NAME = GCDWebServer;
 				SDKROOT = macosx;
@@ -1155,6 +1157,7 @@
 		1DEB928708733DD80010E9CD /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				DEAD_CODE_STRIPPING = YES;
 				MACOSX_DEPLOYMENT_TARGET = 12;
 				PRODUCT_NAME = GCDWebServer;
 				SDKROOT = macosx;
@@ -1167,13 +1170,42 @@
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				BUNDLE_VERSION_STRING = 3.5.4;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
+				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
+				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
+				CLANG_WARN_EMPTY_BODY = YES;
+				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
+				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
+				CLANG_WARN_QUOTED_INCLUDE_IN_FRAMEWORK_HEADER = NO;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
+				CLANG_WARN_UNREACHABLE_CODE = YES;
+				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
+				DEAD_CODE_STRIPPING = YES;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
+				ENABLE_TESTABILITY = YES;
+				ENABLE_USER_SCRIPT_SANDBOXING = YES;
+				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_OPTIMIZATION_LEVEL = 0;
 				GCC_PREPROCESSOR_DEFINITIONS = "DEBUG=1";
 				GCC_PREPROCESSOR_DEFINITIONS_NOT_USED_IN_PRECOMPS = __GCDWEBSERVER_ENABLE_TESTING__;
+				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
+				GCC_WARN_ABOUT_RETURN_TYPE = YES;
+				GCC_WARN_UNDECLARED_SELECTOR = YES;
+				GCC_WARN_UNINITIALIZED_AUTOS = YES;
+				GCC_WARN_UNUSED_FUNCTION = YES;
+				GCC_WARN_UNUSED_VARIABLE = YES;
 				HEADER_SEARCH_PATHS = "$(SDKROOT)/usr/include/libxml2";
 				ONLY_ACTIVE_ARCH = YES;
 				PRODUCT_BUNDLE_IDENTIFIER = "net.pol-online.GCDWebServers";
+				STRING_CATALOG_GENERATE_SYMBOLS = YES;
 				SWIFT_ACTIVE_COMPILATION_CONDITIONS = DEBUG;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
 				SWIFT_VERSION = 5.0;
@@ -1208,11 +1240,39 @@
 				ALWAYS_SEARCH_USER_PATHS = NO;
 				BUNDLE_VERSION_STRING = 3.5.4;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
+				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
+				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
+				CLANG_WARN_EMPTY_BODY = YES;
+				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
+				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
+				CLANG_WARN_QUOTED_INCLUDE_IN_FRAMEWORK_HEADER = NO;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
+				CLANG_WARN_UNREACHABLE_CODE = YES;
+				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
+				DEAD_CODE_STRIPPING = YES;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
+				ENABLE_USER_SCRIPT_SANDBOXING = YES;
+				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_PREPROCESSOR_DEFINITIONS_NOT_USED_IN_PRECOMPS = __GCDWEBSERVER_ENABLE_TESTING__;
 				GCC_TREAT_WARNINGS_AS_ERRORS = YES;
+				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
+				GCC_WARN_ABOUT_RETURN_TYPE = YES;
+				GCC_WARN_UNDECLARED_SELECTOR = YES;
+				GCC_WARN_UNINITIALIZED_AUTOS = YES;
+				GCC_WARN_UNUSED_FUNCTION = YES;
+				GCC_WARN_UNUSED_VARIABLE = YES;
 				HEADER_SEARCH_PATHS = "$(SDKROOT)/usr/include/libxml2";
 				PRODUCT_BUNDLE_IDENTIFIER = "net.pol-online.GCDWebServers";
+				STRING_CATALOG_GENERATE_SYMBOLS = YES;
 				SWIFT_COMPILATION_MODE = wholemodule;
 				SWIFT_TREAT_WARNINGS_AS_ERRORS = YES;
 				SWIFT_VERSION = 5.0;
@@ -1223,10 +1283,12 @@
 		CEE28CE41AE004D800F4023C /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				DEAD_CODE_STRIPPING = YES;
 				DEFINES_MODULE = YES;
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
+				ENABLE_MODULE_VERIFIER = NO;
 				INFOPLIST_FILE = Frameworks/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
@@ -1234,6 +1296,8 @@
 					"@loader_path/Frameworks",
 				);
 				MACOSX_DEPLOYMENT_TARGET = 12;
+				MODULE_VERIFIER_SUPPORTED_LANGUAGE_STANDARDS = "gnu17 gnu++14";
+				PRODUCT_BUNDLE_IDENTIFIER = "${PRODUCT_BUNDLE_IDENTIFIER}";
 				PRODUCT_NAME = GCDWebServers;
 				SDKROOT = macosx;
 				SKIP_INSTALL = YES;
@@ -1243,10 +1307,12 @@
 		CEE28CE51AE004D800F4023C /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				DEAD_CODE_STRIPPING = YES;
 				DEFINES_MODULE = YES;
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
+				ENABLE_MODULE_VERIFIER = NO;
 				INFOPLIST_FILE = Frameworks/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
@@ -1254,6 +1320,8 @@
 					"@loader_path/Frameworks",
 				);
 				MACOSX_DEPLOYMENT_TARGET = 12;
+				MODULE_VERIFIER_SUPPORTED_LANGUAGE_STANDARDS = "gnu17 gnu++14";
+				PRODUCT_BUNDLE_IDENTIFIER = "${PRODUCT_BUNDLE_IDENTIFIER}";
 				PRODUCT_NAME = GCDWebServers;
 				SDKROOT = macosx;
 				SKIP_INSTALL = YES;
@@ -1263,10 +1331,12 @@
 		CEE28D031AE0052000F4023C /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CODE_SIGN_IDENTITY = "";
 				DEFINES_MODULE = YES;
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
+				ENABLE_MODULE_VERIFIER = NO;
 				INFOPLIST_FILE = Frameworks/Info.plist;
 				IPHONEOS_DEPLOYMENT_TARGET = 16;
 				LD_RUNPATH_SEARCH_PATHS = (
@@ -1275,6 +1345,8 @@
 					"@loader_path/Frameworks",
 				);
 				MODULEMAP_FILE = Frameworks/module.modulemap;
+				MODULE_VERIFIER_SUPPORTED_LANGUAGE_STANDARDS = "gnu17 gnu++14";
+				PRODUCT_BUNDLE_IDENTIFIER = "${PRODUCT_BUNDLE_IDENTIFIER}";
 				PRODUCT_NAME = GCDWebServers;
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
@@ -1285,10 +1357,12 @@
 		CEE28D041AE0052000F4023C /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CODE_SIGN_IDENTITY = "";
 				DEFINES_MODULE = YES;
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
+				ENABLE_MODULE_VERIFIER = NO;
 				INFOPLIST_FILE = Frameworks/Info.plist;
 				IPHONEOS_DEPLOYMENT_TARGET = 16;
 				LD_RUNPATH_SEARCH_PATHS = (
@@ -1297,6 +1371,8 @@
 					"@loader_path/Frameworks",
 				);
 				MODULEMAP_FILE = Frameworks/module.modulemap;
+				MODULE_VERIFIER_SUPPORTED_LANGUAGE_STANDARDS = "gnu17 gnu++14";
+				PRODUCT_BUNDLE_IDENTIFIER = "${PRODUCT_BUNDLE_IDENTIFIER}";
 				PRODUCT_NAME = GCDWebServers;
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
@@ -1307,17 +1383,18 @@
 		E240392F1BA09207000B7089 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				DEAD_CODE_STRIPPING = YES;
 				FRAMEWORK_SEARCH_PATHS = (
 					"$(DEVELOPER_FRAMEWORKS_DIR)",
 					"$(inherited)",
 				);
+				GENERATE_INFOPLIST_FILE = YES;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/../Frameworks",
 					"@loader_path/../Frameworks",
 				);
 				MACOSX_DEPLOYMENT_TARGET = 12;
-				GENERATE_INFOPLIST_FILE = YES;
 				PRODUCT_NAME = Tests;
 				SDKROOT = macosx;
 				WARNING_CFLAGS = (
@@ -1330,17 +1407,18 @@
 		E24039301BA09207000B7089 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				DEAD_CODE_STRIPPING = YES;
 				FRAMEWORK_SEARCH_PATHS = (
 					"$(DEVELOPER_FRAMEWORKS_DIR)",
 					"$(inherited)",
 				);
+				GENERATE_INFOPLIST_FILE = YES;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/../Frameworks",
 					"@loader_path/../Frameworks",
 				);
 				MACOSX_DEPLOYMENT_TARGET = 12;
-				GENERATE_INFOPLIST_FILE = YES;
 				PRODUCT_NAME = Tests;
 				SDKROOT = macosx;
 				WARNING_CFLAGS = (
@@ -1353,6 +1431,7 @@
 		E274F877187E77D8009E0582 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				DEAD_CODE_STRIPPING = YES;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 			};
 			name = Debug;
@@ -1360,6 +1439,7 @@
 		E274F878187E77D8009E0582 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				DEAD_CODE_STRIPPING = YES;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 			};
 			name = Release;
@@ -1367,18 +1447,22 @@
 		E2DDD1901BE69404002CE867 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CODE_SIGN_IDENTITY = "";
 				CODE_SIGN_STYLE = Manual;
 				DEFINES_MODULE = YES;
 				DEVELOPMENT_TEAM = "";
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
+				ENABLE_MODULE_VERIFIER = NO;
 				INFOPLIST_FILE = Frameworks/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
 					"@loader_path/Frameworks",
 				);
+				MODULE_VERIFIER_SUPPORTED_LANGUAGE_STANDARDS = "gnu17 gnu++14";
+				PRODUCT_BUNDLE_IDENTIFIER = "${PRODUCT_BUNDLE_IDENTIFIER}";
 				PRODUCT_NAME = GCDWebServers;
 				PROVISIONING_PROFILE_SPECIFIER = "";
 				SDKROOT = appletvos;
@@ -1390,18 +1474,22 @@
 		E2DDD1911BE69404002CE867 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CODE_SIGN_IDENTITY = "";
 				CODE_SIGN_STYLE = Manual;
 				DEFINES_MODULE = YES;
 				DEVELOPMENT_TEAM = "";
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
 				DYLIB_INSTALL_NAME_BASE = "@rpath";
+				ENABLE_MODULE_VERIFIER = NO;
 				INFOPLIST_FILE = Frameworks/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
 					"@loader_path/Frameworks",
 				);
+				MODULE_VERIFIER_SUPPORTED_LANGUAGE_STANDARDS = "gnu17 gnu++14";
+				PRODUCT_BUNDLE_IDENTIFIER = "${PRODUCT_BUNDLE_IDENTIFIER}";
 				PRODUCT_NAME = GCDWebServers;
 				PROVISIONING_PROFILE_SPECIFIER = "";
 				SDKROOT = appletvos;

GCDWebServer.xcodeproj/xcshareddata/xcschemes/GCDWebServers (Mac).xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1130"
+   LastUpgradeVersion = "2650"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"

GCDWebServer.xcodeproj/xcshareddata/xcschemes/GCDWebServers (iOS).xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1130"
+   LastUpgradeVersion = "2650"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"

GCDWebServer.xcodeproj/xcshareddata/xcschemes/GCDWebServers (tvOS).xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1130"
+   LastUpgradeVersion = "2650"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"

GCDWebServer/Core/GCDWebServer.m

@@ -124,7 +124,7 @@ static void _SignalHandler(int signal) {
 // https://developer.apple.com/library/mac/documentation/General/Conceptual/ConcurrencyProgrammingGuide/OperationQueues/OperationQueues.html
 // The main queue works with the application’s run loop to interleave the execution of queued tasks with the execution of other event sources attached to the run loop
 // TODO: Ensure all scheduled blocks on the main queue are also executed
-static void _ExecuteMainThreadRunLoopSources() {
+static void _ExecuteMainThreadRunLoopSources(void) {
   SInt32 result;
   do {
     result = CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0.0, true);

GCDWebServer/Core/GCDWebServerConnection.m

@@ -779,7 +779,7 @@ static inline BOOL _CompareResources(NSString* responseETag, NSString* requestET
 
 - (GCDWebServerResponse*)overrideResponse:(GCDWebServerResponse*)response forRequest:(GCDWebServerRequest*)request {
   if ((response.statusCode >= 200) && (response.statusCode < 300) && _CompareResources(response.eTag, request.ifNoneMatch, response.lastModifiedDate, request.ifModifiedSince)) {
-    NSInteger code = [request.method isEqualToString:@"HEAD"] || [request.method isEqualToString:@"GET"] ? kGCDWebServerHTTPStatusCode_NotModified : kGCDWebServerHTTPStatusCode_PreconditionFailed;
+    NSInteger code = [request.method isEqualToString:@"HEAD"] || [request.method isEqualToString:@"GET"] ? (NSInteger)kGCDWebServerHTTPStatusCode_NotModified : (NSInteger)kGCDWebServerHTTPStatusCode_PreconditionFailed;
     GCDWebServerResponse* newResponse = [GCDWebServerResponse responseWithStatusCode:code];
     newResponse.cacheControlMaxAge = response.cacheControlMaxAge;
     newResponse.lastModifiedDate = response.lastModifiedDate;

GCDWebServer/Core/GCDWebServerFunctions.m

@@ -48,7 +48,7 @@ static NSDateFormatter* _dateFormatterISO8601 = nil;
 static dispatch_queue_t _dateFormatterQueue = NULL;
 
 // TODO: Handle RFC 850 and ANSI C's asctime() format
-void GCDWebServerInitializeFunctions() {
+void GCDWebServerInitializeFunctions(void) {
   GWS_DCHECK([NSThread isMainThread]);  // NSDateFormatter should be initialized on main thread
   if (_dateFormatterRFC822 == nil) {
     _dateFormatterRFC822 = [[NSDateFormatter alloc] init];