diff --git a/stdlib/public/Concurrency/CMakeLists.txt b/stdlib/public/Concurrency/CMakeLists.txt
index c7b0e6de87f56..ef4d0d51451d8 100644
--- a/stdlib/public/Concurrency/CMakeLists.txt
+++ b/stdlib/public/Concurrency/CMakeLists.txt
@@ -283,8 +283,8 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB AND SWIFT_SHOULD_BUILD_EMBEDDED_CONCURRENC
       endif()
 
       if("${mod}" MATCHES "-macos$")
-        set(extra_c_compile_flags -D__MACH__ -D__APPLE__ -ffreestanding -stdlib=libc++)
-        set(extra_swift_compile_flags -Xcc -D__MACH__ -Xcc -D__APPLE__ -Xcc -ffreestanding)
+        set(extra_c_compile_flags -ffreestanding -stdlib=libc++)
+        set(extra_swift_compile_flags -Xcc -ffreestanding)
       endif()
 
     elseif (SWIFT_HOST_VARIANT STREQUAL "wasi")
diff --git a/stdlib/public/Platform/CMakeLists.txt b/stdlib/public/Platform/CMakeLists.txt
index 29a973ef09f47..9ae7a977ac400 100644
--- a/stdlib/public/Platform/CMakeLists.txt
+++ b/stdlib/public/Platform/CMakeLists.txt
@@ -115,9 +115,9 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
         Darwin.swift.gyb
       
       SWIFT_COMPILE_FLAGS
-        -Xcc -D__MACH__ -Xcc -D__APPLE__ -Xcc -ffreestanding -enable-experimental-feature Embedded
+        -Xcc -ffreestanding -enable-experimental-feature Embedded
       C_COMPILE_FLAGS
-        -D__MACH__ -D__APPLE__ -ffreestanding
+        -ffreestanding
       MODULE_DIR "${CMAKE_BINARY_DIR}/lib/swift/embedded"
       SDK "embedded"
       ARCHITECTURE "${arch}"
diff --git a/stdlib/public/Synchronization/CMakeLists.txt b/stdlib/public/Synchronization/CMakeLists.txt
index f7167514c9789..d924943cee70f 100644
--- a/stdlib/public/Synchronization/CMakeLists.txt
+++ b/stdlib/public/Synchronization/CMakeLists.txt
@@ -171,7 +171,7 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
 
       SWIFT_COMPILE_FLAGS
         ${SWIFT_SYNCHRNOIZATION_SWIFT_FLAGS}
-        -Xcc -D__MACH__ -Xcc -D__APPLE__ -Xcc -ffreestanding -enable-experimental-feature Embedded
+        -Xcc -ffreestanding -enable-experimental-feature Embedded
 
       MODULE_DIR "${CMAKE_BINARY_DIR}/lib/swift/embedded"
       SDK "embedded"
diff --git a/stdlib/public/Volatile/CMakeLists.txt b/stdlib/public/Volatile/CMakeLists.txt
index 3f890e5768c4e..bf08132740c2d 100644
--- a/stdlib/public/Volatile/CMakeLists.txt
+++ b/stdlib/public/Volatile/CMakeLists.txt
@@ -42,10 +42,10 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
       Volatile.swift
       
       SWIFT_COMPILE_FLAGS
-        -Xcc -D__MACH__ -Xcc -D__APPLE__ -Xcc -ffreestanding -enable-experimental-feature Embedded
+        -Xcc -ffreestanding -enable-experimental-feature Embedded
         -parse-stdlib
       C_COMPILE_FLAGS
-        -D__MACH__ -D__APPLE__ -ffreestanding
+        -ffreestanding
       MODULE_DIR "${CMAKE_BINARY_DIR}/lib/swift/embedded"
       SDK "embedded"
       ARCHITECTURE "${arch}"
diff --git a/stdlib/public/core/CMakeLists.txt b/stdlib/public/core/CMakeLists.txt
index 0565fde539898..4f58c0a2172ff 100644
--- a/stdlib/public/core/CMakeLists.txt
+++ b/stdlib/public/core/CMakeLists.txt
@@ -516,7 +516,7 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
       ${SWIFTLIB_EMBEDDED_SOURCES}
       GYB_SOURCES ${SWIFTLIB_EMBEDDED_GYB_SOURCES}
       SWIFT_COMPILE_FLAGS
-        ${swift_stdlib_compile_flags} -Xcc -D__MACH__ -Xcc -D__APPLE__ -Xcc -ffreestanding -enable-experimental-feature Embedded
+        ${swift_stdlib_compile_flags} -Xcc -ffreestanding -enable-experimental-feature Embedded
         -Xfrontend -enable-ossa-modules
       MODULE_DIR "${CMAKE_BINARY_DIR}/lib/swift/embedded"
       SDK "embedded"
diff --git a/stdlib/public/stubs/Unicode/CMakeLists.txt b/stdlib/public/stubs/Unicode/CMakeLists.txt
index 6c68ebb48a096..7e60f517574b2 100644
--- a/stdlib/public/stubs/Unicode/CMakeLists.txt
+++ b/stdlib/public/stubs/Unicode/CMakeLists.txt
@@ -21,7 +21,7 @@ if(SWIFT_SHOULD_BUILD_EMBEDDED_STDLIB)
     if (SWIFT_HOST_VARIANT STREQUAL "linux")
       set(extra_c_compile_flags -ffreestanding)
     elseif (SWIFT_HOST_VARIANT STREQUAL "macosx")
-      set(extra_c_compile_flags -D__MACH__ -D__APPLE__ -ffreestanding)
+      set(extra_c_compile_flags -ffreestanding)
     endif()
     list(APPEND extra_c_compile_flags -nostdinc++)
 
diff --git a/test/embedded/fragile-reference.swift b/test/embedded/fragile-reference.swift
index fde4a8f8589f1..9ee8c4e6d8575 100644
--- a/test/embedded/fragile-reference.swift
+++ b/test/embedded/fragile-reference.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -target armv7-apple-none-macho -module-name main -parse-as-library -Xcc -D__MACH__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
-// RUN: %target-swift-frontend -target arm64-apple-none-macho -module-name main -parse-as-library -Xcc -D__MACH__ -Xcc -D__arm64__ -Xcc -D__APPLE__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target armv7-apple-none-macho -module-name main -parse-as-library -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target arm64-apple-none-macho -module-name main -parse-as-library -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 // REQUIRES: swift_in_compiler
 // REQUIRES: CODEGENERATOR=ARM
 // REQUIRES: embedded_stdlib_cross_compiling
diff --git a/test/embedded/no-allocations-print.swift b/test/embedded/no-allocations-print.swift
index 5dad9fccb0b78..6b4ebb3ea448e 100644
--- a/test/embedded/no-allocations-print.swift
+++ b/test/embedded/no-allocations-print.swift
@@ -1,7 +1,7 @@
 // RUN: %target-swift-emit-ir %s -enable-experimental-feature Embedded -no-allocations
 
-// RUN: %target-swift-emit-ir -target armv7-apple-none-macho -no-allocations -Xcc -D__MACH__ %s -enable-experimental-feature Embedded
-// RUN: %target-swift-emit-ir -target arm64-apple-none-macho -no-allocations -Xcc -D__MACH__ -Xcc -D__arm64__ -Xcc -D__APPLE__ %s -enable-experimental-feature Embedded
+// RUN: %target-swift-emit-ir -target armv7-apple-none-macho -no-allocations %s -enable-experimental-feature Embedded
+// RUN: %target-swift-emit-ir -target arm64-apple-none-macho -no-allocations %s -enable-experimental-feature Embedded
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
diff --git a/test/embedded/optionset2.swift b/test/embedded/optionset2.swift
index bb19e680f9877..59c976872fa9a 100644
--- a/test/embedded/optionset2.swift
+++ b/test/embedded/optionset2.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -target armv7-apple-none-macho -Xcc -D__MACH__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
-// RUN: %target-swift-frontend -target arm64-apple-none-macho -Xcc -D__MACH__ -Xcc -D__arm64__ -Xcc -D__APPLE__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target armv7-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target arm64-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
diff --git a/test/embedded/ouroboros-bug.swift b/test/embedded/ouroboros-bug.swift
index a98be86316073..08472ab80c216 100644
--- a/test/embedded/ouroboros-bug.swift
+++ b/test/embedded/ouroboros-bug.swift
@@ -3,8 +3,8 @@
 // code, but in the embedded Swift's runtime that's somewhat reasonable thing
 // to do (but is to be avoided because of this).
 
-// RUN: %target-swift-frontend -target armv7-apple-none-macho -assert-config Debug -Osize -Xcc -D__MACH__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
-// RUN: %target-swift-frontend -target arm64-apple-none-macho -assert-config Debug -Osize -Xcc -D__MACH__ -Xcc -D__arm64__ -Xcc -D__APPLE__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target armv7-apple-none-macho -assert-config Debug -Osize -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target arm64-apple-none-macho -assert-config Debug -Osize -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
diff --git a/test/embedded/ptrauth-none-macho.swift b/test/embedded/ptrauth-none-macho.swift
index 79467331be3d4..057a542d3f800 100644
--- a/test/embedded/ptrauth-none-macho.swift
+++ b/test/embedded/ptrauth-none-macho.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -target arm64e-apple-none-macho -enable-experimental-feature Embedded -emit-ir %s -o - -Xcc -D__APPLE__ -Xcc -D__MACH__ | %FileCheck %s
-// RUN: %target-swift-frontend -target arm64e-apple-macos14 -enable-experimental-feature Embedded -emit-ir %s -o - -Xcc -D__APPLE__ -Xcc -D__MACH__ | %FileCheck %s
+// RUN: %target-swift-frontend -target arm64e-apple-none-macho -enable-experimental-feature Embedded -emit-ir %s -o - | %FileCheck %s
+// RUN: %target-swift-frontend -target arm64e-apple-macos14 -enable-experimental-feature Embedded -emit-ir %s -o - | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: OS=macosx
diff --git a/test/embedded/stdlib-array.swift b/test/embedded/stdlib-array.swift
index 1956186a8ac2c..9657921f5aea8 100644
--- a/test/embedded/stdlib-array.swift
+++ b/test/embedded/stdlib-array.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -target armv7-apple-none-macho -Xcc -D__MACH__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
-// RUN: %target-swift-frontend -target arm64-apple-none-macho -Xcc -D__MACH__ -Xcc -D__arm64__ -Xcc -D__APPLE__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target armv7-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target arm64-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
diff --git a/test/embedded/stdlib-basic.swift b/test/embedded/stdlib-basic.swift
index 30b4f605262b2..2fa2f7e3e1d00 100644
--- a/test/embedded/stdlib-basic.swift
+++ b/test/embedded/stdlib-basic.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -target armv7-apple-none-macho -Xcc -D__MACH__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
-// RUN: %target-swift-frontend -target arm64-apple-none-macho -Xcc -D__MACH__ -Xcc -D__arm64__ -Xcc -D__APPLE__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target armv7-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target arm64-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: CODEGENERATOR=ARM
diff --git a/test/embedded/stdlib-dictionary.swift b/test/embedded/stdlib-dictionary.swift
index 1942b5a26ae30..53b37e7218ee7 100644
--- a/test/embedded/stdlib-dictionary.swift
+++ b/test/embedded/stdlib-dictionary.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -target armv7-apple-none-macho -Xcc -D__MACH__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
-// RUN: %target-swift-frontend -target arm64-apple-none-macho -Xcc -D__MACH__ -Xcc -D__arm64__ -Xcc -D__APPLE__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target armv7-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target arm64-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
diff --git a/test/embedded/stdlib-random.swift b/test/embedded/stdlib-random.swift
index e10836109cfbc..c9472fe305d22 100644
--- a/test/embedded/stdlib-random.swift
+++ b/test/embedded/stdlib-random.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -target armv7-apple-none-macho -Xcc -D__MACH__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
-// RUN: %target-swift-frontend -target arm64-apple-none-macho -Xcc -D__MACH__ -Xcc -D__arm64__ -Xcc -D__APPLE__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target armv7-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target arm64-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
diff --git a/test/embedded/stdlib-set.swift b/test/embedded/stdlib-set.swift
index 533929bd9229d..e81506d843012 100644
--- a/test/embedded/stdlib-set.swift
+++ b/test/embedded/stdlib-set.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -target armv7-apple-none-macho -Xcc -D__MACH__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
-// RUN: %target-swift-frontend -target arm64-apple-none-macho -Xcc -D__MACH__ -Xcc -D__arm64__ -Xcc -D__APPLE__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target armv7-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target arm64-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib
diff --git a/test/embedded/stdlib-strings-interpolation3.swift b/test/embedded/stdlib-strings-interpolation3.swift
index 4c2bb9acd93da..7631046caed3e 100644
--- a/test/embedded/stdlib-strings-interpolation3.swift
+++ b/test/embedded/stdlib-strings-interpolation3.swift
@@ -1,6 +1,6 @@
-// RUN: %target-swift-frontend -target armv7-apple-none-macho -module-name main -parse-as-library -Xcc -D__MACH__ -emit-ir %s -enable-experimental-feature Embedded
-// RUN: %target-swift-frontend -target armv7-apple-none-macho -module-name main -parse-as-library -Xcc -D__MACH__ -emit-ir %s -enable-experimental-feature Embedded -O
-// RUN: %target-swift-frontend -target armv7-apple-none-macho -module-name main -parse-as-library -Xcc -D__MACH__ -emit-ir %s -enable-experimental-feature Embedded -Osize
+// RUN: %target-swift-frontend -target armv7-apple-none-macho -module-name main -parse-as-library -emit-ir %s -enable-experimental-feature Embedded
+// RUN: %target-swift-frontend -target armv7-apple-none-macho -module-name main -parse-as-library -emit-ir %s -enable-experimental-feature Embedded -O
+// RUN: %target-swift-frontend -target armv7-apple-none-macho -module-name main -parse-as-library -emit-ir %s -enable-experimental-feature Embedded -Osize
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: CODEGENERATOR=ARM
diff --git a/test/embedded/stdlib-types.swift b/test/embedded/stdlib-types.swift
index 74fb85b88f76d..cbd2b65e2d947 100644
--- a/test/embedded/stdlib-types.swift
+++ b/test/embedded/stdlib-types.swift
@@ -1,5 +1,5 @@
-// RUN: %target-swift-frontend -target armv7-apple-none-macho -Xcc -D__MACH__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
-// RUN: %target-swift-frontend -target arm64-apple-none-macho -Xcc -D__MACH__ -Xcc -D__arm64__ -Xcc -D__APPLE__ -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target armv7-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
+// RUN: %target-swift-frontend -target arm64-apple-none-macho -emit-ir %s -enable-experimental-feature Embedded | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: optimized_stdlib