diff --git a/Android.mk b/Android.mk
index 893ca07..9601daa 100644
--- a/Android.mk
+++ b/Android.mk
@@ -24,13 +24,13 @@
 # Reactor with LLVM 3.0 doesn't support ARM.  Use Subzero as the Reactor JIT
 # back-end on ARM.
 ifeq ($(TARGET_ARCH),$(filter $(TARGET_ARCH),arm))
-use_subzero := true
+SWIFTSHADER_USE_SUBZERO := true
 endif
 endif
 
 
 # Check whether SwiftShader requires full C++ 11 support.
-ifdef use_subzero
+ifdef SWIFTSHADER_USE_SUBZERO
 SWIFTSHADER_REQUIRES_CXX11 := true
 endif
 
@@ -41,7 +41,7 @@
 ifeq ($(SWIFTSHADER_REQUIRES_CXX11),true)
 # Full C++ 11 support is only available from Marshmallow and up.
 ifeq ($(shell test $(PLATFORM_SDK_VERSION) -lt 23 && echo PreMarshmallow),PreMarshmallow)
-unsupported_build := true
+SWIFTSHADER_UNSUPPORTED_BUILD := true
 endif
 endif
 
@@ -49,17 +49,17 @@
 # Check whether $(TARGET_ARCH) is supported.
 ifeq ($(SWIFTSHADER_LLVM_VERSION),3)
 ifneq ($(TARGET_ARCH),$(filter $(TARGET_ARCH),x86 x86_64 arm))
-unsupported_build := true
+SWIFTSHADER_UNSUPPORTED_BUILD := true
 endif
 endif
 
 ifeq ($(SWIFTSHADER_LLVM_VERSION),7)
 ifneq ($(TARGET_ARCH),$(filter $(TARGET_ARCH),x86 x86_64 arm arm64))
-unsupported_build := true
+SWIFTSHADER_UNSUPPORTED_BUILD := true
 endif
 endif
 
 
-ifndef unsupported_build
+ifndef SWIFTSHADER_UNSUPPORTED_BUILD
 include $(call all-makefiles-under,$(LOCAL_PATH))
 endif
diff --git a/src/Android.mk b/src/Android.mk
index 8559689..3695926 100644
--- a/src/Android.mk
+++ b/src/Android.mk
@@ -6,7 +6,7 @@
 	$(LOCAL_PATH)/OpenGL/ \
 	$(LOCAL_PATH)
 
-ifdef use_subzero
+ifdef SWIFTSHADER_USE_SUBZERO
 
 COMMON_C_INCLUDES += \
 	$(LOCAL_PATH)/../third_party/subzero/ \
@@ -59,7 +59,7 @@
 	Main/FrameBufferAndroid.cpp \
 	Main/SwiftConfig.cpp
 
-ifdef use_subzero
+ifdef SWIFTSHADER_USE_SUBZERO
 COMMON_SRC_FILES += \
 	Reactor/SubzeroReactor.cpp \
 	Reactor/Routine.cpp \
diff --git a/src/OpenGL/libGLES_CM/Android.mk b/src/OpenGL/libGLES_CM/Android.mk
index 30be9ba..624b350 100644
--- a/src/OpenGL/libGLES_CM/Android.mk
+++ b/src/OpenGL/libGLES_CM/Android.mk
@@ -56,7 +56,7 @@
 	$(LOCAL_PATH)/../../Shader/ \
 	$(LOCAL_PATH)/../../Main/
 
-ifdef use_subzero
+ifdef SWIFTSHADER_USE_SUBZERO
 COMMON_STATIC_LIBRARIES := libsubzero
 else
 COMMON_STATIC_LIBRARIES := libLLVM_swiftshader
diff --git a/src/OpenGL/libGLESv2/Android.mk b/src/OpenGL/libGLESv2/Android.mk
index b4b98fe..f92358b 100644
--- a/src/OpenGL/libGLESv2/Android.mk
+++ b/src/OpenGL/libGLESv2/Android.mk
@@ -65,7 +65,7 @@
 	$(LOCAL_PATH)/../../Shader/ \
 	$(LOCAL_PATH)/../../Main/
 
-ifdef use_subzero
+ifdef SWIFTSHADER_USE_SUBZERO
 COMMON_STATIC_LIBRARIES := libsubzero
 else
 COMMON_STATIC_LIBRARIES := libLLVM_swiftshader