Issue 3296 - Enable ia32/x86 Android builds

Makefile

 ARCH := x64
 
-ANDROID_PARAMETERS = target_arch=arm OS=android
-ANDROID_PARAMETERS += android_target_arch=arm
+ANDROID_PARAMETERS = OS=android
+ifneq ($(ANDROID_ARCH),)
+ifeq ($(ANDROID_ARCH),arm)
+ANDROID_PARAMETERS += target_arch=arm android_target_arch=arm
 ANDROID_PARAMETERS += arm_neon=0 armv7=0 arm_fpu=off vfp3=off
 ANDROID_PARAMETERS += arm_float_abi=default
+ANDROID_ABI = armeabi-v7a
+else ifeq ($(ANDROID_ARCH),ia32)
+ANDROID_PARAMETERS += target_arch=x86 android_target_arch=x86
+ANDROID_ABI = x86
+else
+$(error "Unsupported Android architecture: $(ANDROID_ARCH))
+endif
+ANDROID_DEST_DIR = android_$(ANDROID_ARCH).release
+endif
 
 TEST_EXECUTABLE = build/out/Debug/tests
 
-.PHONY: all test clean v8_android android docs
+.PHONY: all test clean docs v8_android_multi android_multi android_x86 \
+        android_arm
 
 all:
         third_party/gyp/gyp --depth=. -f make -I common.gypi --generator-output=build -Dtarget_arch=$(ARCH) libadblockplus.gyp
         $(MAKE) -C build
 
 test: all
 ifdef FILTER
         $(TEST_EXECUTABLE) --gtest_filter=$(FILTER)
 else
         $(TEST_EXECUTABLE)
 endif
 
 docs:
         doxygen
 
 clean:
         $(RM) -r build docs
 
-v8_android:
+android_x86:
+        ANDROID_ARCH="ia32" $(MAKE) android_multi
+
+android_arm:
+        ANDROID_ARCH="arm" $(MAKE) android_multi
+
+ifneq ($(ANDROID_ARCH),)
+v8_android_multi:
         mkdir -p third_party/v8/build/gyp
         cp -f third_party/v8_gyp_launcher third_party/v8/build/gyp/gyp
         DEFINES="${ANDROID_PARAMETERS}" \
         OUTDIR=../../build \
-        $(MAKE) -C third_party/v8 android_arm.release
+        $(MAKE) -C third_party/v8 $(ANDROID_DEST_DIR)
 
-android: v8_android
-        GYP_DEFINES="${ANDROID_PARAMETERS}" \
+android_multi: v8_android_multi
+        GYP_DEFINES="${ANDROID_PARAMETERS} ANDROID_ARCH=$(ANDROID_ARCH)" \
         third_party/gyp/gyp --depth=. -f make-android -I common.gypi --generator-output=build -Gandroid_ndk_version=r9 libadblockplus.gyp
         $(ANDROID_NDK_ROOT)/ndk-build -C build installed_modules \
         BUILDTYPE=Release \
+        APP_ABI=$(ANDROID_ABI) \
         APP_PLATFORM=android-9 \
         APP_STL=c++_static \
         APP_BUILD_SCRIPT=Makefile \
         NDK_TOOLCHAIN_VERSION=clang3.4 \
         NDK_PROJECT_PATH=. \
         NDK_OUT=. \
-        NDK_APP_DST_DIR=android_arm.release
+        NDK_APP_DST_DIR=$(ANDROID_DEST_DIR)
+endif
+