diff --git a/CMakeLists.txt b/CMakeLists.txt
index f71324f85f..145d1e0a22 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -289,7 +289,7 @@ else ()
 endif ()
 
 # set necessary flags to compile code as is
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${TARGET_M} -std=gnu99 ${COMMON_COMPILE_OPTIONS} -Wimplicit")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${TARGET_M} -std=gnu11 ${COMMON_COMPILE_OPTIONS} -Wimplicit")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${TARGET_M} -std=gnu++14 ${COMMON_COMPILE_OPTIONS} -Wnon-virtual-dtor")
 set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${TARGET_M}")
 set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${CMAKE_SHARED_LINKER_FLAGS} ${PIE_FLAG}")
diff --git a/OpenRCT2.xcodeproj/project.pbxproj b/OpenRCT2.xcodeproj/project.pbxproj
index 0878788a73..b7715d83b8 100644
--- a/OpenRCT2.xcodeproj/project.pbxproj
+++ b/OpenRCT2.xcodeproj/project.pbxproj
@@ -243,10 +243,10 @@
 		D41B73EF1C2101890080A7B9 /* libcurl.tbd in Frameworks */ = {isa = PBXBuildFile; fileRef = D41B73EE1C2101890080A7B9 /* libcurl.tbd */; };
 		D41B741D1C210A7A0080A7B9 /* libiconv.tbd in Frameworks */ = {isa = PBXBuildFile; fileRef = D41B741C1C210A7A0080A7B9 /* libiconv.tbd */; };
 		D41B74731C2125E50080A7B9 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = D41B74721C2125E50080A7B9 /* Assets.xcassets */; };
+		D429FF421E36ABCD009342A6 /* tile_inspector.c in Sources */ = {isa = PBXBuildFile; fileRef = D429FF401E36ABCD009342A6 /* tile_inspector.c */; };
 		D433A5001E4A861F00D9A6DF /* SawyerChunk.cpp in Sources */ = {isa = PBXBuildFile; fileRef = D433A4FA1E4A861F00D9A6DF /* SawyerChunk.cpp */; };
 		D433A5011E4A861F00D9A6DF /* SawyerChunkReader.cpp in Sources */ = {isa = PBXBuildFile; fileRef = D433A4FC1E4A861F00D9A6DF /* SawyerChunkReader.cpp */; };
 		D433A5021E4A861F00D9A6DF /* SawyerChunkWriter.cpp in Sources */ = {isa = PBXBuildFile; fileRef = D433A4FE1E4A861F00D9A6DF /* SawyerChunkWriter.cpp */; };
-		D429FF421E36ABCD009342A6 /* tile_inspector.c in Sources */ = {isa = PBXBuildFile; fileRef = D429FF401E36ABCD009342A6 /* tile_inspector.c */; };
 		D43407D61D0E14BE00C2B3D4 /* CopyFramebufferShader.cpp in Sources */ = {isa = PBXBuildFile; fileRef = D43407C01D0E14BE00C2B3D4 /* CopyFramebufferShader.cpp */; };
 		D43407D81D0E14BE00C2B3D4 /* DrawImageShader.cpp in Sources */ = {isa = PBXBuildFile; fileRef = D43407C41D0E14BE00C2B3D4 /* DrawImageShader.cpp */; };
 		D43407D91D0E14BE00C2B3D4 /* DrawLineShader.cpp in Sources */ = {isa = PBXBuildFile; fileRef = D43407C61D0E14BE00C2B3D4 /* DrawLineShader.cpp */; };
@@ -716,6 +716,9 @@
 		D41B73EE1C2101890080A7B9 /* libcurl.tbd */ = {isa = PBXFileReference; lastKnownFileType = "sourcecode.text-based-dylib-definition"; name = libcurl.tbd; path = usr/lib/libcurl.tbd; sourceTree = SDKROOT; };
 		D41B741C1C210A7A0080A7B9 /* libiconv.tbd */ = {isa = PBXFileReference; lastKnownFileType = "sourcecode.text-based-dylib-definition"; name = libiconv.tbd; path = usr/lib/libiconv.tbd; sourceTree = SDKROOT; };
 		D41B74721C2125E50080A7B9 /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; name = Assets.xcassets; path = distribution/macos/Assets.xcassets; sourceTree = SOURCE_ROOT; };
+		D429FF3F1E36ABB3009342A6 /* tile_inspector.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = tile_inspector.h; sourceTree = "<group>"; };
+		D429FF401E36ABCD009342A6 /* tile_inspector.c */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.c; path = tile_inspector.c; sourceTree = "<group>"; };
+		D429FF411E36ABCD009342A6 /* tile_inspector.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = tile_inspector.h; sourceTree = "<group>"; };
 		D433A4FA1E4A861F00D9A6DF /* SawyerChunk.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = SawyerChunk.cpp; path = rct12/SawyerChunk.cpp; sourceTree = "<group>"; };
 		D433A4FB1E4A861F00D9A6DF /* SawyerChunk.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = SawyerChunk.h; path = rct12/SawyerChunk.h; sourceTree = "<group>"; };
 		D433A4FC1E4A861F00D9A6DF /* SawyerChunkReader.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = SawyerChunkReader.cpp; path = rct12/SawyerChunkReader.cpp; sourceTree = "<group>"; };
@@ -723,9 +726,6 @@
 		D433A4FE1E4A861F00D9A6DF /* SawyerChunkWriter.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = SawyerChunkWriter.cpp; path = rct12/SawyerChunkWriter.cpp; sourceTree = "<group>"; };
 		D433A4FF1E4A861F00D9A6DF /* SawyerChunkWriter.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = SawyerChunkWriter.h; path = rct12/SawyerChunkWriter.h; sourceTree = "<group>"; };
 		D433A5031E4A862F00D9A6DF /* rct12.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = rct12.h; sourceTree = "<group>"; };
-		D429FF3F1E36ABB3009342A6 /* tile_inspector.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = tile_inspector.h; sourceTree = "<group>"; };
-		D429FF401E36ABCD009342A6 /* tile_inspector.c */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.c; path = tile_inspector.c; sourceTree = "<group>"; };
-		D429FF411E36ABCD009342A6 /* tile_inspector.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = tile_inspector.h; sourceTree = "<group>"; };
 		D43407C01D0E14BE00C2B3D4 /* CopyFramebufferShader.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = CopyFramebufferShader.cpp; sourceTree = "<group>"; };
 		D43407C11D0E14BE00C2B3D4 /* CopyFramebufferShader.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = CopyFramebufferShader.h; sourceTree = "<group>"; };
 		D43407C41D0E14BE00C2B3D4 /* DrawImageShader.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = DrawImageShader.cpp; sourceTree = "<group>"; };
@@ -3138,7 +3138,7 @@
 				DEBUG_INFORMATION_FORMAT = dwarf;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				ENABLE_TESTABILITY = YES;
-				GCC_C_LANGUAGE_STANDARD = gnu99;
+				GCC_C_LANGUAGE_STANDARD = gnu11;
 				GCC_DYNAMIC_NO_PIC = NO;
 				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_OPTIMIZATION_LEVEL = 0;
@@ -3186,7 +3186,7 @@
 				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
 				ENABLE_NS_ASSERTIONS = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
-				GCC_C_LANGUAGE_STANDARD = gnu99;
+				GCC_C_LANGUAGE_STANDARD = gnu11;
 				GCC_DYNAMIC_NO_PIC = NO;
 				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_PREPROCESSOR_DEFINITIONS = (
diff --git a/src/openrct2/localisation/localisation.h b/src/openrct2/localisation/localisation.h
index 8a2b671c2c..439db31af5 100644
--- a/src/openrct2/localisation/localisation.h
+++ b/src/openrct2/localisation/localisation.h
@@ -85,9 +85,11 @@ static inline void set_format_arg_body(uint8 *args, size_t offset, uintptr_t val
 }
 
 #define set_format_arg(offset, type, value)	\
-	set_format_arg_body(gCommonFormatArgs, offset, (uintptr_t)value, sizeof(type))
+	do { static_assert(sizeof(type) <= sizeof(uintptr_t), "Type too large"); \
+	set_format_arg_body(gCommonFormatArgs, offset, (uintptr_t)value, sizeof(type)); } while (0)
 
 #define set_map_tooltip_format_arg(offset, type, value) \
-	set_format_arg_body(gMapTooltipFormatArgs, offset, (uintptr_t)value, sizeof(type))
+	do { static_assert(sizeof(type) <= sizeof(uintptr_t), "Type too large"); \
+	set_format_arg_body(gMapTooltipFormatArgs, offset, (uintptr_t)value, sizeof(type)); } while (0)
 
 #endif