diff --git a/cmake/toolchains/android-ndk-common.cmake b/cmake/toolchains/android-ndk-common.cmake
new file mode 100644
index 0000000..58b27a6
--- /dev/null
+++ b/cmake/toolchains/android-ndk-common.cmake
@@ -0,0 +1,11 @@
+if(DRACO_CMAKE_TOOLCHAINS_ANDROID_NDK_COMMON_CMAKE_)
+  return()
+endif()
+set(DRACO_CMAKE_TOOLCHAINS_ANDROID_NDK_COMMON_CMAKE_ 1)
+
+include("${CMAKE_CURRENT_LIST_DIR}/../util.cmake")
+
+require_variable(CMAKE_ANDROID_NDK)
+set(CMAKE_SYSTEM_NAME Android)
+set_variable_if_unset(CMAKE_ANDROID_STL_TYPE c++_static)
+set_variable_if_unset(CMAKE_ANDROID_NDK_TOOLCHAIN_VERSION clang)
diff --git a/cmake/toolchains/arm64-android-ndk-libcpp.cmake b/cmake/toolchains/arm64-android-ndk-libcpp.cmake
index 293e029..efc9cd1 100644
--- a/cmake/toolchains/arm64-android-ndk-libcpp.cmake
+++ b/cmake/toolchains/arm64-android-ndk-libcpp.cmake
@@ -4,9 +4,7 @@ endif()
 set(DRACO_CMAKE_TOOLCHAINS_ARM64_ANDROID_NDK_LIBCPP_CMAKE_ 1)
 
 include("${CMAKE_CURRENT_LIST_DIR}/../util.cmake")
+include("${CMAKE_CURRENT_LIST_DIR}/android-ndk-common.cmake")
 
-set(CMAKE_SYSTEM_NAME Android)
 set(CMAKE_ANDROID_ARCH_ABI arm64-v8a)
-require_variable(CMAKE_ANDROID_NDK)
 set_variable_if_unset(CMAKE_SYSTEM_VERSION 21)
-set_variable_if_unset(CMAKE_ANDROID_STL_TYPE c++_static)
diff --git a/cmake/toolchains/armv7-android-ndk-libcpp.cmake b/cmake/toolchains/armv7-android-ndk-libcpp.cmake
index b4b517c..a1b0a6b 100644
--- a/cmake/toolchains/armv7-android-ndk-libcpp.cmake
+++ b/cmake/toolchains/armv7-android-ndk-libcpp.cmake
@@ -4,9 +4,7 @@ endif()
 set(DRACO_CMAKE_TOOLCHAINS_ARMV7_ANDROID_NDK_LIBCPP_CMAKE_ 1)
 
 include("${CMAKE_CURRENT_LIST_DIR}/../util.cmake")
+include("${CMAKE_CURRENT_LIST_DIR}/android-ndk-common.cmake")
 
-set(CMAKE_SYSTEM_NAME Android)
 set(CMAKE_ANDROID_ARCH_ABI armeabi-v7a)
-require_variable(CMAKE_ANDROID_NDK)
 set_variable_if_unset(CMAKE_SYSTEM_VERSION 18)
-set_variable_if_unset(CMAKE_ANDROID_STL_TYPE c++_static)
diff --git a/cmake/toolchains/default-android-ndk-libcpp.cmake b/cmake/toolchains/default-android-ndk-libcpp.cmake
new file mode 100644
index 0000000..cd1d7ca
--- /dev/null
+++ b/cmake/toolchains/default-android-ndk-libcpp.cmake
@@ -0,0 +1,7 @@
+if(DRACO_CMAKE_TOOLCHAINS_DEFAULT_ANDROID_NDK_LIBCPP_CMAKE_)
+  return()
+endif()
+set(DRACO_CMAKE_TOOLCHAINS_DEFAULT_ANDROID_NDK_LIBCPP_CMAKE_ 1)
+
+include("${CMAKE_CURRENT_LIST_DIR}/../util.cmake")
+include("${CMAKE_CURRENT_LIST_DIR}/android-ndk-common.cmake")
diff --git a/cmake/toolchains/x86-android-ndk-libcpp.cmake b/cmake/toolchains/x86-android-ndk-libcpp.cmake
index ba0778d..38e7d31 100644
--- a/cmake/toolchains/x86-android-ndk-libcpp.cmake
+++ b/cmake/toolchains/x86-android-ndk-libcpp.cmake
@@ -4,9 +4,7 @@ endif()
 set(DRACO_CMAKE_TOOLCHAINS_X86_ANDROID_NDK_LIBCPP_CMAKE_ 1)
 
 include("${CMAKE_CURRENT_LIST_DIR}/../util.cmake")
+include("${CMAKE_CURRENT_LIST_DIR}/android-ndk-common.cmake")
 
-set(CMAKE_SYSTEM_NAME Android)
 set(CMAKE_ANDROID_ARCH_ABI x86)
-require_variable(CMAKE_ANDROID_NDK)
 set_variable_if_unset(CMAKE_SYSTEM_VERSION 18)
-set_variable_if_unset(CMAKE_ANDROID_STL_TYPE c++_static)
diff --git a/cmake/toolchains/x86_64-android-ndk-libcpp.cmake b/cmake/toolchains/x86_64-android-ndk-libcpp.cmake
index 18bba4f..2230e50 100644
--- a/cmake/toolchains/x86_64-android-ndk-libcpp.cmake
+++ b/cmake/toolchains/x86_64-android-ndk-libcpp.cmake
@@ -4,9 +4,7 @@ endif()
 set(DRACO_CMAKE_TOOLCHAINS_X86_64_ANDROID_NDK_LIBCPP_CMAKE_ 1)
 
 include("${CMAKE_CURRENT_LIST_DIR}/../util.cmake")
+include("${CMAKE_CURRENT_LIST_DIR}/android-ndk-common.cmake")
 
-set(CMAKE_SYSTEM_NAME Android)
 set(CMAKE_ANDROID_ARCH_ABI x86_64)
-require_variable(CMAKE_ANDROID_NDK)
 set_variable_if_unset(CMAKE_SYSTEM_VERSION 21)
-set_variable_if_unset(CMAKE_ANDROID_STL_TYPE c++_static)
diff --git a/cmake/util.cmake b/cmake/util.cmake
index d5333ef..8c82f46 100644
--- a/cmake/util.cmake
+++ b/cmake/util.cmake
@@ -63,11 +63,11 @@ macro(require_variable var_name)
   set_variable_if_unset(${var_name} "")
 endmacro()
 
-# Sets $var_name to $default_value if not already set in the environment.
+# Sets $var_name to $default_value if not already set.
 macro(set_variable_if_unset var_name default_value)
   if(NOT "$ENV{${var_name}}" STREQUAL "")
     set(${var_name} $ENV{${var_name}})
-  else()
+  elseif(NOT ${var_name})
     set(${var_name} ${default_value})
   endif()
 endmacro()