Use the new compiler inline annotations when available

Author: vsanthanam

Sources/JBirdCodableSupport/CodingKeys/SnakeCaseCodingKey.swift

@@ -47,14 +47,25 @@ struct SnakeCaseCodingKey: CodingKey {
             var out = String()
             out.reserveCapacity(bytes.count + bytes.count / 4)
 
-            @inline(__always)
-            func appendLowercasedASCII(_ b: UInt8) {
-                if isUpper(b) {
-                    out.append(Character(UnicodeScalar(b + 32)))
-                } else {
-                    out.append(Character(UnicodeScalar(b)))
+            #if compiler(>=6.3)
+                @inline(always)
+                func appendLowercasedASCII(_ b: UInt8) {
+                    if isUpper(b) {
+                        out.append(Character(UnicodeScalar(b + 32)))
+                    } else {
+                        out.append(Character(UnicodeScalar(b)))
+                    }
                 }
-            }
+            #else
+                @inline(__always)
+                func appendLowercasedASCII(_ b: UInt8) {
+                    if isUpper(b) {
+                        out.append(Character(UnicodeScalar(b + 32)))
+                    } else {
+                        out.append(Character(UnicodeScalar(b)))
+                    }
+                }
+            #endif
 
             for i in bytes.indices {
                 let b = bytes[i]

Sources/JBirdCore/Deserialization/Deserialization.swift

@@ -736,33 +736,65 @@ extension JSON {
     #endif
 
     #if os(Windows)
-        @inline(__always)
-        private static func calculateMaxDepth() -> size_t {
-            var low: ULONG_PTR = 0
-            var high: ULONG_PTR = 0
-            GetCurrentThreadStackLimits(&low, &high)
-
-            let stackBytes = size_t(high &- low)
-            return min(1024, max(16, stackBytes / 512))
-        }
-
+        #if compiler(>=6.3)
+            @inline(always)
+            private static func calculateMaxDepth() -> size_t {
+                var low: ULONG_PTR = 0
+                var high: ULONG_PTR = 0
+                GetCurrentThreadStackLimits(&low, &high)
+
+                let stackBytes = size_t(high &- low)
+                return min(1024, max(16, stackBytes / 512))
+            }
+        #else
+            @inline(__always)
+            private static func calculateMaxDepth() -> size_t {
+                var low: ULONG_PTR = 0
+                var high: ULONG_PTR = 0
+                GetCurrentThreadStackLimits(&low, &high)
+
+                let stackBytes = size_t(high &- low)
+                return min(1024, max(16, stackBytes / 512))
+            }
+        #endif
     #elseif os(WASI) || arch(wasm32)
-        @inline(__always)
-        private static func calculateMaxDepth() -> size_t {
-            // There is no way to do this on Web Assembly. Makes sense.
-            256
-        }
+        #if compiler(>=6.3)
+            @inline(always)
+            private static func calculateMaxDepth() -> size_t {
+                // There is no way to do this on Web Assembly. Makes sense.
+                256
+            }
+        #else
+            @inline(__always)
+            private static func calculateMaxDepth() -> size_t {
+                // There is no way to do this on Web Assembly. Makes sense.
+                256
+            }
+        #endif
     #else
-        @inline(__always)
-        private static func calculateMaxDepth() -> size_t {
-            var attr = pthread_attr_t()
-            pthread_attr_init(&attr)
-            defer { pthread_attr_destroy(&attr) }
-
-            var size: size_t = 0
-            pthread_attr_getstacksize(&attr, &size)
-            return min(1024, max(16, size / 512))
-        }
+        #if compiler(>=6.3)
+            @inline(always)
+            private static func calculateMaxDepth() -> size_t {
+                var attr = pthread_attr_t()
+                pthread_attr_init(&attr)
+                defer { pthread_attr_destroy(&attr) }
+
+                var size: size_t = 0
+                pthread_attr_getstacksize(&attr, &size)
+                return min(1024, max(16, size / 512))
+            }
+        #else
+            @inline(__always)
+            private static func calculateMaxDepth() -> size_t {
+                var attr = pthread_attr_t()
+                pthread_attr_init(&attr)
+                defer { pthread_attr_destroy(&attr) }
+
+                var size: size_t = 0
+                pthread_attr_getstacksize(&attr, &size)
+                return min(1024, max(16, size / 512))
+            }
+        #endif
     #endif
 
     private static func calculateMaxInputSize() -> size_t {