diff --git a/Sources/TSCBasic/Await.swift b/Sources/TSCBasic/Await.swift
index d61fd4e3..62a4435e 100644
--- a/Sources/TSCBasic/Await.swift
+++ b/Sources/TSCBasic/Await.swift
@@ -14,16 +14,12 @@
 ///                   should be passed to the async method's completion handler.
 /// - Returns: The value wrapped by the async method's result.
 /// - Throws: The error wrapped by the async method's result
-//#if compiler(>=5.8)
-//@available(*, noasync)
-//#endif
+@available(*, noasync)
 public func tsc_await<T, ErrorType>(_ body: (@escaping (Result<T, ErrorType>) -> Void) -> Void) throws -> T {
     return try tsc_await(body).get()
 }
 
-//#if compiler(>=5.8)
-//@available(*, noasync)
-//#endif
+@available(*, noasync)
 public func tsc_await<T>(_ body: (@escaping (T) -> Void) -> Void) -> T {
     let condition = Condition()
     var result: T? = nil
diff --git a/Sources/TSCBasic/Closable.swift b/Sources/TSCBasic/Closable.swift
index 5a7bf71f..168fcc35 100644
--- a/Sources/TSCBasic/Closable.swift
+++ b/Sources/TSCBasic/Closable.swift
@@ -9,7 +9,7 @@
 */
 
 /// Closable entity is one that manages underlying resources and needs to be closed for cleanup
-/// The intent of this method is for the sole owner of the refernece/handle of the resource to close it completely, comapred to releasing a shared resource.
+/// The intent of this method is for the sole owner of the reference/handle of the resource to close it completely, compared to releasing a shared resource.
 public protocol Closable {
     func close() throws
 }
diff --git a/Sources/TSCBasic/CollectionExtensions.swift b/Sources/TSCBasic/CollectionExtensions.swift
index b0ba5df6..87383338 100644
--- a/Sources/TSCBasic/CollectionExtensions.swift
+++ b/Sources/TSCBasic/CollectionExtensions.swift
@@ -27,7 +27,7 @@ extension Collection {
 extension Collection where Element: Hashable {
     /// Returns a new list of element removing duplicate elements.
     ///
-    /// Note: The order of elements is preseved.
+    /// Note: The order of elements is preserved.
     /// Complexity: O(n)
     public func spm_uniqueElements() -> [Element] {
         var set = Set<Element>()
diff --git a/Sources/TSCBasic/DeltaAlgorithm.swift b/Sources/TSCBasic/DeltaAlgorithm.swift
index 60391826..93ed3f5d 100644
--- a/Sources/TSCBasic/DeltaAlgorithm.swift
+++ b/Sources/TSCBasic/DeltaAlgorithm.swift
@@ -65,7 +65,7 @@ public struct DeltaAlgorithm<Change: Hashable>: Sendable {
         return result
     }
 
-    /// Minimizes a set of `changes` which has been partioned into smaller sets,
+    /// Minimizes a set of `changes` which has been partitioned into smaller sets,
     /// by attempting to remove individual subsets.
     func delta(
         changes: Set<Change>,
diff --git a/Sources/TSCBasic/HashAlgorithms.swift b/Sources/TSCBasic/HashAlgorithms.swift
index b3bbaa4a..59c706da 100644
--- a/Sources/TSCBasic/HashAlgorithms.swift
+++ b/Sources/TSCBasic/HashAlgorithms.swift
@@ -60,7 +60,7 @@ struct InternalSHA256: HashAlgorithm {
     private static let blockBitSize = 512
 
     /// The initial hash value.
-    private static let initalHashValue: [UInt32] = [
+    private static let initialHashValue: [UInt32] = [
         0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
     ]
 
@@ -89,7 +89,7 @@ struct InternalSHA256: HashAlgorithm {
         let messageBlocks = input.blocks(size: Self.blockBitSize / 8)
 
         /// The hash that is being computed.
-        var hash = Self.initalHashValue
+        var hash = Self.initialHashValue
 
         // Process each block.
         for block in messageBlocks {
diff --git a/Sources/TSCBasic/Process/Process.swift b/Sources/TSCBasic/Process/Process.swift
index 8cd2efe6..fe82a799 100644
--- a/Sources/TSCBasic/Process/Process.swift
+++ b/Sources/TSCBasic/Process/Process.swift
@@ -324,6 +324,7 @@ public final class Process {
 
     /// The result of the process execution. Available after process is terminated.
     /// This will block while the process is awaiting result
+    @available(*, noasync)
     @available(*, deprecated, message: "use waitUntilExit instead")
     public var result: ProcessResult? {
         return self.stateLock.withLock {
@@ -679,24 +680,11 @@ public final class Process {
         defer { posix_spawn_file_actions_destroy(&fileActions) }
 
         if let workingDirectory = workingDirectory?.pathString {
-          #if canImport(Darwin)
-            // The only way to set a workingDirectory is using an availability-gated initializer, so we don't need
-            // to handle the case where the posix_spawn_file_actions_addchdir_np method is unavailable. This check only
-            // exists here to make the compiler happy.
-            if #available(macOS 10.15, *) {
-                posix_spawn_file_actions_addchdir_np(&fileActions, workingDirectory)
-            }
-          #elseif os(FreeBSD)
-                posix_spawn_file_actions_addchdir_np(&fileActions, workingDirectory)
-          #elseif os(Linux)
             guard SPM_posix_spawn_file_actions_addchdir_np_supported() else {
                 throw Process.Error.workingDirectoryNotSupported
             }
 
             SPM_posix_spawn_file_actions_addchdir_np(&fileActions, workingDirectory)
-          #else
-            throw Process.Error.workingDirectoryNotSupported
-          #endif
         }
 
         var stdinPipe: [Int32] = [-1, -1]
@@ -856,7 +844,9 @@ public final class Process {
     public func waitUntilExit() async throws -> ProcessResult {
         try await withCheckedThrowingContinuation { continuation in
             DispatchQueue.processConcurrent.async {
-                self.waitUntilExit(continuation.resume(with:))
+                self.waitUntilExit {
+                    continuation.resume(with: $0)
+                }
             }
         }
     }
@@ -1127,9 +1117,7 @@ extension Process {
     ///   - loggingHandler: Handler for logging messages
     ///   - queue: Queue to use for callbacks
     ///   - completion: A completion handler to return the process result
-//    #if compiler(>=5.8)
-//    @available(*, noasync)
-//    #endif
+    @available(*, noasync)
     static public func popen(
         arguments: [String],
         environmentBlock: ProcessEnvironmentBlock = ProcessEnv.block,
@@ -1157,6 +1145,7 @@ extension Process {
     }
 
     @_disfavoredOverload
+    @available(*, noasync)
     @available(*, deprecated, renamed: "popen(arguments:environmentBlock:loggingHandler:queue:completion:)")
     static public func popen(
         arguments: [String],
@@ -1182,9 +1171,7 @@ extension Process {
     ///     will be inherited.
     ///   - loggingHandler: Handler for logging messages
     /// - Returns: The process result.
-//    #if compiler(>=5.8)
-//    @available(*, noasync)
-//    #endif
+    @available(*, noasync)
     @discardableResult
     static public func popen(
         arguments: [String],
@@ -1202,6 +1189,7 @@ extension Process {
     }
 
     @_disfavoredOverload
+    @available(*, noasync)
     @available(*, deprecated, renamed: "popen(arguments:environmentBlock:loggingHandler:)")
     @discardableResult
     static public func popen(
@@ -1220,9 +1208,7 @@ extension Process {
     ///     will be inherited.
     ///   - loggingHandler: Handler for logging messages
     /// - Returns: The process result.
-//    #if compiler(>=5.8)
-//    @available(*, noasync)
-//    #endif
+    @available(*, noasync)
     @discardableResult
     static public func popen(
         args: String...,
@@ -1233,6 +1219,7 @@ extension Process {
     }
 
     @_disfavoredOverload
+    @available(*, noasync)
     @available(*, deprecated, renamed: "popen(args:environmentBlock:loggingHandler:)")
     @discardableResult
     static public func popen(
@@ -1251,9 +1238,7 @@ extension Process {
     ///     will be inherited.
     ///   - loggingHandler: Handler for logging messages
     /// - Returns: The process output (stdout + stderr).
-//    #if compiler(>=5.8)
-//    @available(*, noasync)
-//    #endif
+    @available(*, noasync)
     @discardableResult
     static public func checkNonZeroExit(
         arguments: [String],
@@ -1276,6 +1261,7 @@ extension Process {
     }
 
     @_disfavoredOverload
+    @available(*, noasync)
     @available(*, deprecated, renamed: "checkNonZeroExit(arguments:environmentBlock:loggingHandler:)")
     @discardableResult
     static public func checkNonZeroExit(
@@ -1294,9 +1280,7 @@ extension Process {
     ///     will be inherited.
     ///   - loggingHandler: Handler for logging messages
     /// - Returns: The process output (stdout + stderr).
-//    #if compiler(>=5.8)
-//    @available(*, noasync)
-//    #endif
+    @available(*, noasync)
     @discardableResult
     static public func checkNonZeroExit(
         args: String...,
@@ -1307,6 +1291,7 @@ extension Process {
     }
 
     @_disfavoredOverload
+    @available(*, noasync)
     @available(*, deprecated, renamed: "checkNonZeroExit(args:environmentBlock:loggingHandler:)")
     @discardableResult
     static public func checkNonZeroExit(
diff --git a/Sources/TSCBasic/Process/ProcessSet.swift b/Sources/TSCBasic/Process/ProcessSet.swift
index 7235c5e0..3ebd1269 100644
--- a/Sources/TSCBasic/Process/ProcessSet.swift
+++ b/Sources/TSCBasic/Process/ProcessSet.swift
@@ -65,9 +65,7 @@ public final class ProcessSet {
     /// Terminate all the processes. This method blocks until all processes in the set are terminated.
     ///
     /// A process set cannot be used once it has been asked to terminate.
-//    #if compiler(>=5.8)
-//    @available(*, noasync)
-//    #endif
+    @available(*, noasync)
     public func terminate() {
         // Mark a process set as cancelled.
         serialQueue.sync {
diff --git a/Sources/TSCBasic/RegEx.swift b/Sources/TSCBasic/RegEx.swift
index 14e8cc8a..86ad3698 100644
--- a/Sources/TSCBasic/RegEx.swift
+++ b/Sources/TSCBasic/RegEx.swift
@@ -12,6 +12,7 @@ import Foundation
 
 /// A helpful wrapper around NSRegularExpression.
 /// - SeeAlso: NSRegularExpression
+@available(*, deprecated, message: "Use Swift `Regex` type instead")
 public struct RegEx {
     private let regex: NSRegularExpression
     public typealias Options = NSRegularExpression.Options
diff --git a/Sources/TSCBasic/SortedArray.swift b/Sources/TSCBasic/SortedArray.swift
index 3a9679a2..f236fafe 100644
--- a/Sources/TSCBasic/SortedArray.swift
+++ b/Sources/TSCBasic/SortedArray.swift
@@ -90,7 +90,7 @@ public struct SortedArray<Element>: CustomStringConvertible {
 
         var lhs = elements[lhsIndex], rhs = newElements[rhsIndex]
 
-        // Equivalent to a merge sort, "pop" and append the max elemeent of
+        // Equivalent to a merge sort, "pop" and append the max element of
         // each array until either array is empty.
         for index in elements.indices.reversed() {
             if areInIncreasingOrder(lhs, rhs) {
diff --git a/Sources/TSCBasic/TemporaryFile.swift b/Sources/TSCBasic/TemporaryFile.swift
index 76cddf75..feb4b680 100644
--- a/Sources/TSCBasic/TemporaryFile.swift
+++ b/Sources/TSCBasic/TemporaryFile.swift
@@ -60,7 +60,7 @@ public func determineTempDirectory(_ dir: AbsolutePath? = nil) throws -> Absolut
     return tmpDir
 }
 
-/// The closure argument of the `body` closue of `withTemporaryFile`.
+/// The closure argument of the `body` closure of `withTemporaryFile`.
 public struct TemporaryFile {
     /// If specified during init, the temporary file name begins with this prefix.
     let prefix: String
diff --git a/Sources/TSCTestSupport/misc.swift b/Sources/TSCTestSupport/misc.swift
index 3201b4c1..573164f2 100644
--- a/Sources/TSCTestSupport/misc.swift
+++ b/Sources/TSCTestSupport/misc.swift
@@ -44,6 +44,8 @@ public func testWithTemporaryDirectory(
     }
 }
 
+@available(*, noasync)
+@available(*, deprecated, message: "Use Process.checkNonZeroExit(arguments:) instead.")
 public func systemQuietly(_ args: [String]) throws {
     // Discard the output, by default.
     //
@@ -51,6 +53,8 @@ public func systemQuietly(_ args: [String]) throws {
     try Process.checkNonZeroExit(arguments: args)
 }
 
+@available(*, noasync)
+@available(*, deprecated, message: "Use Process.checkNonZeroExit(_:) instead.")
 public func systemQuietly(_ args: String...) throws {
     try systemQuietly(args)
 }
diff --git a/Sources/TSCclibc/include/process.h b/Sources/TSCclibc/include/process.h
index 2d9c806e..da96606b 100644
--- a/Sources/TSCclibc/include/process.h
+++ b/Sources/TSCclibc/include/process.h
@@ -1,4 +1,4 @@
-#if defined(__linux__)
+#if !defined(_WIN32)
 
 #include <spawn.h>
 #include <stdbool.h>
diff --git a/Sources/TSCclibc/process.c b/Sources/TSCclibc/process.c
index 5bd1011a..d6ac2a06 100644
--- a/Sources/TSCclibc/process.c
+++ b/Sources/TSCclibc/process.c
@@ -1,34 +1,54 @@
-#if defined(__linux__)
+#if !defined(_WIN32)
 
+#if defined(__linux__)
 #ifndef _GNU_SOURCE
 #define _GNU_SOURCE /* for posix_spawn_file_actions_addchdir_np */
 #endif
+#endif
+
+#ifndef __GLIBC_PREREQ
+#define __GLIBC_PREREQ(maj, min) 0
+#endif
 
 #include <errno.h>
 
 #include "process.h"
 
 int SPM_posix_spawn_file_actions_addchdir_np(posix_spawn_file_actions_t *restrict file_actions, const char *restrict path) {
-#if defined(__GLIBC__)
-#  if __GLIBC_PREREQ(2, 29)
-    return posix_spawn_file_actions_addchdir_np(file_actions, path);
-#  else
+#if defined(__GLIBC__) && !__GLIBC_PREREQ(2, 29)
+    // Glibc versions prior to 2.29 don't support posix_spawn_file_actions_addchdir_np, impacting:
+    //  - Amazon Linux 2 (EoL mid-2025)
     return ENOSYS;
-#  endif
-#else
+#elif defined(__ANDROID__) && __ANDROID_API__ < 34
+    // Android versions prior to 14 (API level 34) don't support posix_spawn_file_actions_addchdir_np
     return ENOSYS;
+#elif defined(__OpenBSD__) || defined(__QNX__)
+    // Currently missing as of:
+    //  - OpenBSD 7.5 (April 2024)
+    //  - QNX 8 (December 2023)
+    return ENOSYS;
+#elif defined(__GLIBC__) || defined(__APPLE__) || defined(__FreeBSD__) || defined(__ANDROID__) || defined(__musl__)
+    // Pre-standard posix_spawn_file_actions_addchdir_np version available in:
+    //  - Solaris 11.3 (October 2015)
+    //  - Glibc 2.29 (February 2019)
+    //  - macOS 10.15 (October 2019)
+    //  - musl 1.1.24 (October 2019)
+    //  - FreeBSD 13.1 (May 2022)
+    //  - Android 14 (October 2023)
+    return posix_spawn_file_actions_addchdir_np((posix_spawn_file_actions_t *)file_actions, path);
+#else
+    // Standardized posix_spawn_file_actions_addchdir version (POSIX.1-2024, June 2024) available in:
+    //  - Solaris 11.4 (August 2018)
+    //  - NetBSD 10.0 (March 2024)
+    return posix_spawn_file_actions_addchdir((posix_spawn_file_actions_t *)file_actions, path);
 #endif
 }
 
 bool SPM_posix_spawn_file_actions_addchdir_np_supported() {
-#if defined(__GLIBC__)
-#  if __GLIBC_PREREQ(2, 29)
-    return true;
-#  else
+#if (defined(__GLIBC__) && !__GLIBC_PREREQ(2, 29)) || (defined(__OpenBSD__)) || (defined(__ANDROID__) && __ANDROID_API__ < 34) || (defined(__QNX__))
     return false;
-#  endif
 #else
-    return false;
+    return true;
 #endif
 }
 
diff --git a/Tests/TSCBasicTests/ProcessTests.swift b/Tests/TSCBasicTests/ProcessTests.swift
index 9e2aec2c..6d3d208f 100644
--- a/Tests/TSCBasicTests/ProcessTests.swift
+++ b/Tests/TSCBasicTests/ProcessTests.swift
@@ -428,12 +428,7 @@ class ProcessTests: XCTestCase {
     }
 
     func testWorkingDirectory() throws {
-        guard #available(macOS 10.15, *) else {
-            // Skip this test since it's not supported in this OS.
-            return
-        }
-
-      #if os(Linux) || os(Android)
+      #if !os(Windows)
         guard SPM_posix_spawn_file_actions_addchdir_np_supported() else {
             // Skip this test since it's not supported in this OS.
             return
@@ -478,9 +473,7 @@ fileprivate extension Process {
         self.init(arguments: [Self.script(scriptName)] + arguments, environment: Self.env(), outputRedirection: outputRedirection)
     }
 
-//    #if compiler(>=5.8)
-//    @available(*, noasync)
-//    #endif
+    @available(*, noasync)
     static func checkNonZeroExit(
         scriptName: String,
         environment: [String: String] = ProcessEnv.vars,
@@ -498,9 +491,7 @@ fileprivate extension Process {
         return try await checkNonZeroExit(args: script(scriptName), environment: environment, loggingHandler: loggingHandler)
     }
 
-//    #if compiler(>=5.8)
-//    @available(*, noasync)
-//    #endif
+    @available(*, noasync)
     @discardableResult
     static func popen(
         scriptName: String,