Make sure the -DANDROID compilation flag is always included.

packages/react-native-gradle-plugin/src/main/kotlin/com/facebook/react/utils/NdkConfiguratorUtils.kt

@@ -40,16 +40,22 @@ internal object NdkConfiguratorUtils {
         // Parameters should be provided in an additive manner (do not override what
         // the user provided, but allow for sensible defaults).
         val cmakeArgs = ext.defaultConfig.externalNativeBuild.cmake.arguments
-        if ("-DPROJECT_BUILD_DIR" !in cmakeArgs) {
+        if (cmakeArgs.none { it.startsWith("-DPROJECT_BUILD_DIR") }) {
           cmakeArgs.add("-DPROJECT_BUILD_DIR=${project.buildDir}")
         }
-        if ("-DREACT_ANDROID_DIR" !in cmakeArgs) {
+        if (cmakeArgs.none { it.startsWith("-DREACT_ANDROID_DIR") }) {
           cmakeArgs.add(
               "-DREACT_ANDROID_DIR=${extension.reactNativeDir.file("ReactAndroid").get().asFile}")
         }
-        if ("-DANDROID_STL" !in cmakeArgs) {
+        if (cmakeArgs.none { it.startsWith("-DANDROID_STL") }) {
           cmakeArgs.add("-DANDROID_STL=c++_shared")
         }
+        // Due to the new NDK toolchain file, the C++ flags gets overridden between compilation
+        // units. This is causing some libraries to don't be compiled with -DANDROID and other
+        // crucial flags. This can be revisited once we bump to NDK 25/26
+        if (cmakeArgs.none { it.startsWith("-DANDROID_USE_LEGACY_TOOLCHAIN_FILE") }) {
+          cmakeArgs.add("-DANDROID_USE_LEGACY_TOOLCHAIN_FILE=ON")
+        }
 
         val architectures = project.getReactNativeArchitectures()
         // abiFilters are split ABI are not compatible each other, so we set the abiFilters

packages/react-native/ReactAndroid/build.gradle

@@ -473,7 +473,10 @@ android {
                     "-DREACT_BUILD_DIR=$buildDir",
                     "-DANDROID_STL=c++_shared",
                     "-DANDROID_TOOLCHAIN=clang",
-                    "-DANDROID_PLATFORM=android-21"
+                    "-DANDROID_PLATFORM=android-21",
+                    // Due to https://github.com/android/ndk/issues/1693 we're losing Android
+                    // specific compilation flags. This can be removed once we moved to NDK 25/26
+                    "-DANDROID_USE_LEGACY_TOOLCHAIN_FILE=ON"
 
                 targets "jsijniprofiler",
                     "reactnativeblob",

packages/react-native/ReactAndroid/hermes-engine/build.gradle

@@ -154,6 +154,9 @@ android {
                 // We intentionally build Hermes with Intl support only. This is to simplify
                 // the build setup and to avoid overcomplicating the build-type matrix.
                 arguments "-DHERMES_ENABLE_INTL=True"
+                // Due to https://github.com/android/ndk/issues/1693 we're losing Android
+                // specific compilation flags. This can be removed once we moved to NDK 25/26
+                arguments "-DANDROID_USE_LEGACY_TOOLCHAIN_FILE=ON"
                 targets "libhermes"
             }
         }

packages/react-native/ReactAndroid/src/main/jni/CMakeLists.txt

@@ -190,7 +190,6 @@ add_executable(reactnative_unittest
     -fexceptions
     -frtti
     -std=c++17
-    -DANDROID
     -DHERMES_ENABLE_DEBUGGER)
 
   target_link_libraries(reactnative_unittest