diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2bb1099078..11e6511c53 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -13,6 +13,14 @@ project(Foundation
   LANGUAGES C Swift)
 enable_testing()
 
+if(NOT SWIFT_SYSTEM_NAME)
+  if(CMAKE_SYSTEM_NAME STREQUAL Darwin)
+    set(SWIFT_SYSTEM_NAME macosx)
+  else()
+    set(SWIFT_SYSTEM_NAME "$<LOWER_CASE:${CMAKE_SYSTEM_NAME}>")
+  endif()
+endif()
+
 # NOTE(compnerd) default to /MD or /MDd by default based on the configuration.
 # Cache the variable to allow the user to alter the configuration.
 set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>DLL" CACHE
@@ -38,6 +46,7 @@ set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
 set(CMAKE_Swift_MODULE_DIRECTORY ${CMAKE_BINARY_DIR}/swift)
 
 option(BUILD_SHARED_LIBS "build shared libraries" ON)
+option(BUILD_FULLY_STATIC "build fully static" NO)
 option(HAS_LIBDISPATCH_API "has libdispatch API" ON)
 option(BUILD_NETWORKING "build FoundationNetworking module" ON)
 option(BUILD_TOOLS "build tools" ON)
@@ -49,6 +58,12 @@ endif()
 
 find_package(ICU COMPONENTS uc i18n REQUIRED OPTIONAL_COMPONENTS data)
 
+# This is needed if we're statically linking, otherwise we can't pull in Dispatch
+# because we won't have RT::rt as a CMake target.
+if(NOT CMAKE_SYSTEM_NAME STREQUAL Android)
+  find_package(LibRT)
+endif()
+
 include(SwiftSupport)
 include(GNUInstallDirs)
 include(XCTest)
@@ -99,13 +114,13 @@ if(NOT BUILD_SHARED_LIBS)
   endif()
 
   install(TARGETS CoreFoundation CFXMLInterface
-    DESTINATION lib/swift_static/$<LOWER_CASE:${CMAKE_SYSTEM_NAME}>)
+    DESTINATION lib/swift_static/${SWIFT_SYSTEM_NAME})
 
   if(BUILD_NETWORKING)
     set_property(GLOBAL APPEND PROPERTY Foundation_EXPORTS
       CFURLSessionInterface)
     install(TARGETS CFURLSessionInterface
-      DESTINATION lib/swift_static/$<LOWER_CASE:${CMAKE_SYSTEM_NAME}>)
+      DESTINATION lib/swift_static/${SWIFT_SYSTEM_NAME})
   endif()
 endif()
 
diff --git a/CoreFoundation/Base.subproj/CFUtilities.c b/CoreFoundation/Base.subproj/CFUtilities.c
index 7c3fc9f8e7..e3fdd98c04 100644
--- a/CoreFoundation/Base.subproj/CFUtilities.c
+++ b/CoreFoundation/Base.subproj/CFUtilities.c
@@ -1675,7 +1675,7 @@ CFDictionaryRef __CFGetEnvironment() {
         extern char **environ;
         char **envp = environ;
 #elif TARGET_OS_LINUX
-#if !defined(environ) && !TARGET_OS_ANDROID
+#if !defined(environ) && !TARGET_OS_ANDROID && !defined(__musl__)
 #define environ __environ
 #endif
         char **envp = environ;
diff --git a/CoreFoundation/Base.subproj/CoreFoundation_Prefix.h b/CoreFoundation/Base.subproj/CoreFoundation_Prefix.h
index bf6f203b5f..928fef002f 100644
--- a/CoreFoundation/Base.subproj/CoreFoundation_Prefix.h
+++ b/CoreFoundation/Base.subproj/CoreFoundation_Prefix.h
@@ -189,7 +189,8 @@ static dispatch_queue_t __ ## PREFIX ## Queue(void) {			\
 #define CF_RETAIN_BALANCED_ELSEWHERE(obj, identified_location) do { } while (0)
 #endif
 
-#if (TARGET_OS_LINUX && !TARGET_OS_ANDROID && !TARGET_OS_CYGWIN) || TARGET_OS_WIN32
+#if !TARGET_OS_MAC
+#if !HAVE_STRLCPY
 CF_INLINE size_t
 strlcpy(char * dst, const char * src, size_t maxlen) {
     const size_t srclen = strlen(src);
@@ -201,7 +202,9 @@ strlcpy(char * dst, const char * src, size_t maxlen) {
     }
     return srclen;
 }
+#endif
 
+#if !HAVE_STRLCAT
 CF_INLINE size_t
 strlcat(char * dst, const char * src, size_t maxlen) {
     const size_t srclen = strlen(src);
@@ -216,6 +219,7 @@ strlcat(char * dst, const char * src, size_t maxlen) {
     return dstlen + srclen;
 }
 #endif
+#endif // !TARGET_OS_MAC
 
 #if TARGET_OS_WIN32
 // Compatibility with boolean.h
@@ -300,7 +304,7 @@ typedef unsigned long fd_mask;
 #endif
     
 
-#if !TARGET_OS_CYGWIN && !TARGET_OS_BSD
+#if !TARGET_OS_MAC && !HAVE_ISSETUGID
 #define issetugid() 0
 #endif
 
diff --git a/CoreFoundation/Base.subproj/ForSwiftFoundationOnly.h b/CoreFoundation/Base.subproj/ForSwiftFoundationOnly.h
index 642151ab34..9dc7379c9d 100644
--- a/CoreFoundation/Base.subproj/ForSwiftFoundationOnly.h
+++ b/CoreFoundation/Base.subproj/ForSwiftFoundationOnly.h
@@ -69,6 +69,7 @@
 #include <features.h>
 #include <termios.h>
 
+#ifdef __GLIBC_PREREQ
 #if __GLIBC_PREREQ(2, 28) == 0
 // required for statx() system call, glibc >=2.28 wraps the kernel function
 #include <sys/syscall.h>
@@ -78,7 +79,7 @@
 #include <linux/fs.h>
 #define AT_STATX_SYNC_AS_STAT   0x0000  /* - Do whatever stat() does */
 #endif //__GLIBC_PREREQ(2. 28)
-
+#endif // defined(__GLIBC_PREREQ)
 #ifndef __NR_statx
 #include <sys/stat.h>
 #endif // not __NR_statx
@@ -562,7 +563,7 @@ CF_CROSS_PLATFORM_EXPORT int _CFOpenFile(const char *path, int opts);
 static inline int _direntNameLength(struct dirent *entry) {
 #ifdef _D_EXACT_NAMLEN  // defined on Linux
     return _D_EXACT_NAMLEN(entry);
-#elif TARGET_OS_ANDROID
+#elif TARGET_OS_LINUX || TARGET_OS_ANDROID
     return strlen(entry->d_name);
 #else
     return entry->d_namlen;
diff --git a/CoreFoundation/CMakeLists.txt b/CoreFoundation/CMakeLists.txt
index beb48d6c86..2e8afc2139 100644
--- a/CoreFoundation/CMakeLists.txt
+++ b/CoreFoundation/CMakeLists.txt
@@ -6,6 +6,9 @@ project(CoreFoundation
   VERSION 1338
   LANGUAGES ASM C)
 
+include(CheckSymbolExists)
+include(CheckIncludeFile)
+
 set(CMAKE_C_STANDARD 99)
 set(CMAKE_C_STANDARD_REQUIRED YES)
 
@@ -70,8 +73,6 @@ if(CMAKE_SYSTEM_NAME STREQUAL Linux OR CMAKE_SYSTEM_NAME STREQUAL Android)
   add_compile_definitions($<$<COMPILE_LANGUAGE:C>:_GNU_SOURCE>)
 
   if(CMAKE_SYSTEM_NAME STREQUAL Linux)
-    include(CheckSymbolExists)
-    include(CheckIncludeFile)
     list(APPEND CMAKE_REQUIRED_DEFINITIONS -D_GNU_SOURCE)
     check_include_file("sched.h" HAVE_SCHED_H)
     if(HAVE_SCHED_H)
@@ -90,6 +91,21 @@ elseif(CMAKE_SYSTEM_NAME STREQUAL Windows)
   endif()
 endif()
 
+# Look for some functions that may not be present on all platforms
+check_symbol_exists(strlcpy "string.h" HAVE_STRLCPY)
+check_symbol_exists(strlcat "string.h" HAVE_STRLCAT)
+check_symbol_exists(issetugid "unistd.h" HAVE_ISSETUGID)
+
+if(HAVE_STRLCPY)
+  add_compile_definitions($<$<COMPILE_LANGUAGE:C>:HAVE_STRLCPY>)
+endif()
+if(HAVE_STRLCAT)
+  add_compile_definitions($<$<COMPILE_LANGUAGE:C>:HAVE_STRLCAT>)
+endif()
+if(HAVE_ISSETUGID)
+  add_compile_definitions($<$<COMPILE_LANGUAGE:C>:HAVE_ISSETUGID>)
+endif()
+
 add_compile_definitions($<$<COMPILE_LANGUAGE:C>:U_SHOW_DRAFT_API>)
 add_compile_definitions($<$<COMPILE_LANGUAGE:C>:CF_BUILDING_CF>)
 
diff --git a/Sources/BlocksRuntime/CMakeLists.txt b/Sources/BlocksRuntime/CMakeLists.txt
index 057302dd43..671627e4ee 100644
--- a/Sources/BlocksRuntime/CMakeLists.txt
+++ b/Sources/BlocksRuntime/CMakeLists.txt
@@ -11,5 +11,5 @@ set_target_properties(BlocksRuntime PROPERTIES
 add_library(BlocksRuntime::BlocksRuntime ALIAS BlocksRuntime)
 
 install(TARGETS BlocksRuntime
-  ARCHIVE DESTINATION lib/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/$<LOWER_CASE:${CMAKE_SYSTEM_NAME}>
-  LIBRARY DESTINATION lib/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/$<LOWER_CASE:${CMAKE_SYSTEM_NAME}>)
+  ARCHIVE DESTINATION lib/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/${SWIFT_SYSTEM_NAME}
+  LIBRARY DESTINATION lib/swift$<$<NOT:$<BOOL:${BUILD_SHARED_LIBS}>>:_static>/${SWIFT_SYSTEM_NAME})
diff --git a/Sources/Foundation/CMakeLists.txt b/Sources/Foundation/CMakeLists.txt
index fc093ce0c8..7154092e29 100644
--- a/Sources/Foundation/CMakeLists.txt
+++ b/Sources/Foundation/CMakeLists.txt
@@ -164,6 +164,11 @@ target_link_libraries(Foundation
     uuid
   PUBLIC
     swiftDispatch)
+if("${CMAKE_C_COMPILER_TARGET}" MATCHES ".*-musl[^-*]$")
+  target_link_libraries(Foundation
+    PUBLIC
+      fts)
+endif()
 set_target_properties(Foundation PROPERTIES
   INSTALL_RPATH "$ORIGIN"
   BUILD_RPATH "$<TARGET_FILE_DIR:swiftDispatch>"
diff --git a/Sources/Foundation/Data.swift b/Sources/Foundation/Data.swift
index 86585a3a86..23254e6b22 100644
--- a/Sources/Foundation/Data.swift
+++ b/Sources/Foundation/Data.swift
@@ -28,6 +28,13 @@
 @usableFromInline let memset = Glibc.memset
 @usableFromInline let memcpy = Glibc.memcpy
 @usableFromInline let memcmp = Glibc.memcmp
+#elseif canImport(Musl)
+@usableFromInline let calloc = Musl.calloc
+@usableFromInline let malloc = Musl.malloc
+@usableFromInline let free = Musl.free
+@usableFromInline let memset = Musl.memset
+@usableFromInline let memcpy = Musl.memcpy
+@usableFromInline let memcmp = Musl.memcmp
 #elseif canImport(WASILibc)
 @usableFromInline let calloc = WASILibc.calloc
 @usableFromInline let malloc = WASILibc.malloc
@@ -48,6 +55,8 @@ internal func malloc_good_size(_ size: Int) -> Int {
 
 #if canImport(Glibc)
 import Glibc
+#elseif canImport(Musl)
+import Musl
 #elseif canImport(WASILibc)
 import WASILibc
 #endif
diff --git a/Sources/Foundation/FileHandle.swift b/Sources/Foundation/FileHandle.swift
index a538a2975e..285bed7059 100644
--- a/Sources/Foundation/FileHandle.swift
+++ b/Sources/Foundation/FileHandle.swift
@@ -22,6 +22,11 @@ import Glibc
 fileprivate let _read = Glibc.read(_:_:_:)
 fileprivate let _write = Glibc.write(_:_:_:)
 fileprivate let _close = Glibc.close(_:)
+#elseif canImport(Musl)
+import Musl
+fileprivate let _read = Musl.read(_:_:_:)
+fileprivate let _write = Musl.write(_:_:_:)
+fileprivate let _close = Musl.close(_:)
 #endif
 
 #if canImport(WinSDK)
diff --git a/Sources/Foundation/Host.swift b/Sources/Foundation/Host.swift
index 5fe7b29c5b..5a72373c6d 100644
--- a/Sources/Foundation/Host.swift
+++ b/Sources/Foundation/Host.swift
@@ -281,7 +281,7 @@ open class Host: NSObject {
             }
             var hints = addrinfo()
             hints.ai_family = PF_UNSPEC
-#if os(macOS) || os(iOS) || os(Android) || os(OpenBSD)
+#if os(macOS) || os(iOS) || os(Android) || os(OpenBSD) || canImport(Musl)
             hints.ai_socktype = SOCK_STREAM
 #else
             hints.ai_socktype = Int32(SOCK_STREAM.rawValue)
diff --git a/Sources/Foundation/NSData.swift b/Sources/Foundation/NSData.swift
index ed9e7f0529..e004c9502a 100644
--- a/Sources/Foundation/NSData.swift
+++ b/Sources/Foundation/NSData.swift
@@ -494,8 +494,10 @@ open class NSData : NSObject, NSCopying, NSMutableCopying, NSSecureCoding {
             let createMode = Int(ucrt.S_IREAD) | Int(ucrt.S_IWRITE)
 #elseif canImport(Darwin)
             let createMode = Int(S_IRUSR) | Int(S_IWUSR) | Int(S_IRGRP) | Int(S_IWGRP) | Int(S_IROTH) | Int(S_IWOTH)
-#else
+#elseif canImport(Glibc)
             let createMode = Int(Glibc.S_IRUSR) | Int(Glibc.S_IWUSR) | Int(Glibc.S_IRGRP) | Int(Glibc.S_IWGRP) | Int(Glibc.S_IROTH) | Int(Glibc.S_IWOTH)
+#elseif canImport(Musl)
+            let createMode = Int(Musl.S_IRUSR) | Int(Musl.S_IWUSR) | Int(Musl.S_IRGRP) | Int(Musl.S_IWGRP) | Int(Musl.S_IROTH) | Int(Musl.S_IWOTH)
 #endif
             guard let fh = FileHandle(path: path, flags: flags, createMode: createMode) else {
                 throw _NSErrorWithErrno(errno, reading: false, path: path)
diff --git a/Sources/Foundation/NSSwiftRuntime.swift b/Sources/Foundation/NSSwiftRuntime.swift
index 04958446d7..c079ed6259 100644
--- a/Sources/Foundation/NSSwiftRuntime.swift
+++ b/Sources/Foundation/NSSwiftRuntime.swift
@@ -14,8 +14,10 @@
 // This mimics the behavior of the swift sdk overlay on Darwin
 #if os(macOS) || os(iOS) || os(tvOS) || os(watchOS)
 @_exported import Darwin
-#elseif os(Linux) || os(Android) || CYGWIN || os(OpenBSD)
+#elseif canImport(Glibc)
 @_exported import Glibc
+#elseif canImport(Musl)
+@_exported import Musl
 #elseif os(WASI)
 @_exported import WASILibc
 #elseif os(Windows)
diff --git a/Sources/Foundation/NSURL.swift b/Sources/Foundation/NSURL.swift
index 9b121d6681..4b6a2a5b98 100644
--- a/Sources/Foundation/NSURL.swift
+++ b/Sources/Foundation/NSURL.swift
@@ -20,6 +20,8 @@ internal let kCFURLWindowsPathStyle = CFURLPathStyle.cfurlWindowsPathStyle
 import Darwin
 #elseif canImport(Glibc)
 import Glibc
+#elseif canImport(Musl)
+import Musl
 #endif
 
 // NOTE: this represents PLATFORM_PATH_STYLE
diff --git a/Sources/Foundation/Process.swift b/Sources/Foundation/Process.swift
index 542cc94cf1..8d5ac46563 100644
--- a/Sources/Foundation/Process.swift
+++ b/Sources/Foundation/Process.swift
@@ -776,7 +776,7 @@ open class Process: NSObject {
         }
 
         var taskSocketPair : [Int32] = [0, 0]
-#if os(macOS) || os(iOS) || os(Android) || os(OpenBSD)
+#if os(macOS) || os(iOS) || os(Android) || os(OpenBSD) || canImport(Musl)
         socketpair(AF_UNIX, SOCK_STREAM, 0, &taskSocketPair)
 #else
         socketpair(AF_UNIX, Int32(SOCK_STREAM.rawValue), 0, &taskSocketPair)
diff --git a/Sources/Foundation/Thread.swift b/Sources/Foundation/Thread.swift
index 7734cf738d..7fbcbb522e 100644
--- a/Sources/Foundation/Thread.swift
+++ b/Sources/Foundation/Thread.swift
@@ -14,6 +14,8 @@ import WinSDK
 
 #if canImport(Glibc)
 import Glibc
+#elseif canImport(Musl)
+import Musl
 #endif
 
 // WORKAROUND_SR9811
@@ -356,13 +358,15 @@ open class Thread : NSObject {
         _cancelled = true
     }
 
+    // ###TODO: Switch these over to using the Swift runtime's backtracer
+    //          once we have Windows support there.
 
     private class func backtraceAddresses<T>(_ body: (UnsafeMutablePointer<UnsafeMutableRawPointer?>, Int) -> [T]) -> [T] {
         // Same as swift/stdlib/public/runtime/Errors.cpp backtrace
         let maxSupportedStackDepth = 128;
         let addrs = UnsafeMutablePointer<UnsafeMutableRawPointer?>.allocate(capacity: maxSupportedStackDepth)
         defer { addrs.deallocate() }
-#if os(Android) || os(OpenBSD)
+#if os(Android) || os(OpenBSD) || canImport(Musl)
         let count = 0
 #elseif os(Windows)
         let count = RtlCaptureStackBackTrace(0, DWORD(maxSupportedStackDepth),
@@ -383,7 +387,7 @@ open class Thread : NSObject {
     }
 
     open class var callStackSymbols: [String] {
-#if os(Android) || os(OpenBSD)
+#if os(Android) || os(OpenBSD) || canImport(Musl)
         return []
 #elseif os(Windows)
         let hProcess: HANDLE = GetCurrentProcess()
diff --git a/Sources/FoundationNetworking/CMakeLists.txt b/Sources/FoundationNetworking/CMakeLists.txt
index 1a8f516e98..183013cc82 100644
--- a/Sources/FoundationNetworking/CMakeLists.txt
+++ b/Sources/FoundationNetworking/CMakeLists.txt
@@ -72,6 +72,14 @@ if(NOT BUILD_SHARED_LIBS)
     PRIVATE
       "SHELL:-Xfrontend -public-autolink-library -Xfrontend curl")
 
+  if(BUILD_FULLY_STATIC)
+    target_compile_options(FoundationNetworking
+      PRIVATE
+        "SHELL:-Xfrontend -public-autolink-library -Xfrontend crypto"
+        "SHELL:-Xfrontend -public-autolink-library -Xfrontend ssl"
+        "SHELL:-Xfrontend -public-autolink-library -Xfrontend z")
+  endif()
+
   # Merge private dependencies into single static objects archive
   set_property(TARGET FoundationNetworking PROPERTY STATIC_LIBRARY_OPTIONS
     $<TARGET_OBJECTS:CFURLSessionInterface>)
diff --git a/Sources/FoundationXML/CMakeLists.txt b/Sources/FoundationXML/CMakeLists.txt
index 944ea25875..5a73f70f58 100644
--- a/Sources/FoundationXML/CMakeLists.txt
+++ b/Sources/FoundationXML/CMakeLists.txt
@@ -23,6 +23,12 @@ if(NOT BUILD_SHARED_LIBS)
     PRIVATE
       "SHELL:-Xfrontend -public-autolink-library -Xfrontend xml2")
 
+  if(BUILD_FULLY_STATIC)
+    target_compile_options(FoundationXML
+      PRIVATE
+        "SHELL:-Xfrontend -public-autolink-library -Xfrontend z")
+  endif()
+
   # Merge private dependencies into single static objects archive
   set_property(TARGET FoundationXML PROPERTY STATIC_LIBRARY_OPTIONS
     $<TARGET_OBJECTS:CFXMLInterface>)
diff --git a/Sources/Tools/plutil/CMakeLists.txt b/Sources/Tools/plutil/CMakeLists.txt
index b1c843506a..30ff29bb0c 100644
--- a/Sources/Tools/plutil/CMakeLists.txt
+++ b/Sources/Tools/plutil/CMakeLists.txt
@@ -28,7 +28,7 @@ if(NOT CMAKE_SYSTEM_NAME MATCHES "Darwin|Windows")
 endif()
 
 set_target_properties(plutil PROPERTIES
-  INSTALL_RPATH "$ORIGIN/../lib/swift/$<LOWER_CASE:${CMAKE_SYSTEM_NAME}>")
+  INSTALL_RPATH "$ORIGIN/../lib/swift/${SWIFT_SYSTEM_NAME}")
 
 
 set_property(GLOBAL APPEND PROPERTY Foundation_EXPORTS plutil)
diff --git a/Sources/Tools/plutil/main.swift b/Sources/Tools/plutil/main.swift
index c9ee783f84..d71d9ba9a2 100644
--- a/Sources/Tools/plutil/main.swift
+++ b/Sources/Tools/plutil/main.swift
@@ -12,6 +12,9 @@ import SwiftFoundation
 #elseif canImport(Glibc)
 import Foundation
 import Glibc
+#elseif canImport(Musl)
+import Foundation
+import Musl
 #elseif canImport(CRT)
 import Foundation
 import CRT
diff --git a/Sources/UUID/CMakeLists.txt b/Sources/UUID/CMakeLists.txt
index fea52c7396..bab43b0f01 100644
--- a/Sources/UUID/CMakeLists.txt
+++ b/Sources/UUID/CMakeLists.txt
@@ -28,7 +28,7 @@ if(NOT BUILD_SHARED_LIBS)
   # TODO(drexin): should be installed in architecture specific folder, once
   # the layout is fixed for non-Darwin platforms
   install(TARGETS uuid
-    ARCHIVE DESTINATION lib/swift_static/$<LOWER_CASE:${CMAKE_SYSTEM_NAME}>
-    LIBRARY DESTINATION lib/swift_static/$<LOWER_CASE:${CMAKE_SYSTEM_NAME}>
+    ARCHIVE DESTINATION lib/swift_static/${SWIFT_SYSTEM_NAME}
+    LIBRARY DESTINATION lib/swift_static/${SWIFT_SYSTEM_NAME}
     RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
 endif()
diff --git a/cmake/modules/FindLibRT.cmake b/cmake/modules/FindLibRT.cmake
new file mode 100644
index 0000000000..0a9f0d80e5
--- /dev/null
+++ b/cmake/modules/FindLibRT.cmake
@@ -0,0 +1,39 @@
+#.rst:
+# FindLibRT
+# ---------
+#
+# Find librt library and headers.
+#
+# The mdoule defines the following variables:
+#
+# ::
+#
+# LibRT_FOUND       - true if librt was found
+# LibRT_INCLUDE_DIR - include search path
+# LibRT_LIBRARIES   - libraries to link
+
+if(UNIX)
+  find_path(LibRT_INCLUDE_DIR
+            NAMES
+              time.h)
+  find_library(LibRT_LIBRARIES rt)
+
+  include(FindPackageHandleStandardArgs)
+  find_package_handle_standard_args(LibRT
+                                    REQUIRED_VARS
+                                      LibRT_LIBRARIES
+                                      LibRT_INCLUDE_DIR)
+
+  if(LibRT_FOUND)
+    if(NOT TARGET RT::rt)
+      add_library(RT::rt UNKNOWN IMPORTED)
+      set_target_properties(RT::rt
+                            PROPERTIES
+                              IMPORTED_LOCATION ${LibRT_LIBRARIES}
+                              INTERFACE_INCLUDE_DIRECTORIES ${LibRT_INCLUDE_DIR})
+    endif()
+  endif()
+
+  mark_as_advanced(LibRT_LIBRARIES LibRT_INCLUDE_DIR)
+endif()
+
diff --git a/cmake/modules/SwiftSupport.cmake b/cmake/modules/SwiftSupport.cmake
index ffb24527eb..ba22becab2 100644
--- a/cmake/modules/SwiftSupport.cmake
+++ b/cmake/modules/SwiftSupport.cmake
@@ -49,12 +49,7 @@ endfunction()
 # Sets ${result_var_name} with the converted OS name derived from
 # CMAKE_SYSTEM_NAME.
 function(get_swift_host_os result_var_name)
-  if(CMAKE_SYSTEM_NAME STREQUAL Darwin)
-    set(${result_var_name} macosx PARENT_SCOPE)
-  else()
-    string(TOLOWER ${CMAKE_SYSTEM_NAME} cmake_system_name_lc)
-    set(${result_var_name} ${cmake_system_name_lc} PARENT_SCOPE)
-  endif()
+  set(${result_var_name} ${SWIFT_SYSTEM_NAME} PARENT_SCOPE)
 endfunction()
 
 function(_install_target module)