Build non-SIMD versions of Stockfish engine

Will be used for CPUs that don't support the best SIMD instructions.

DroidFishApp/build.gradle

@@ -78,6 +78,7 @@ preBuild.dependsOn buildEco
 task copyToAssets(type: Copy, dependsOn: 'externalNativeBuildRelease') {
     from('build/intermediates/ndkBuild/release/obj/local') {
         include '*/stockfish'
+        include '*/stockfish_nosimd'
     }
     into 'src/main/assets'
 }

DroidFishApp/src/main/cpp/stockfish/Android.mk

@@ -23,8 +23,20 @@ endif
 
 include $(CLEAR_VARS)
 LOCAL_MODULE    := stockfish
-LOCAL_SRC_FILES := $(SF_SRC_FILES)
+include $(LOCAL_PATH)/build_sf.mk
-LOCAL_CFLAGS    := -std=c++17 -O2 -fno-exceptions -DNNUE_EMBEDDING_OFF \
+
-                   -fPIE $(MY_ARCH_DEF) -s
+ifeq ($(TARGET_ARCH_ABI),armeabi-v7a)
-LOCAL_LDFLAGS	+= -fPIE -pie -s
+  MY_ARCH_DEF :=
-include $(BUILD_EXECUTABLE)
+  include $(CLEAR_VARS)
+  LOCAL_MODULE    := stockfish_nosimd
+  include $(LOCAL_PATH)/build_sf.mk
+  stockfish : stockfish_nosimd
+endif
+
+ifeq ($(TARGET_ARCH_ABI),x86)
+  MY_ARCH_DEF :=
+  include $(CLEAR_VARS)
+  LOCAL_MODULE    := stockfish_nosimd
+  include $(LOCAL_PATH)/build_sf.mk
+  stockfish : stockfish_nosimd
+endif

DroidFishApp/src/main/cpp/stockfish/build_sf.mk

@@ -0,0 +1,5 @@
+LOCAL_SRC_FILES := $(SF_SRC_FILES)
+LOCAL_CFLAGS    := -std=c++17 -O2 -fno-exceptions -DNNUE_EMBEDDING_OFF \
+                   -fPIE $(MY_ARCH_DEF) -s
+LOCAL_LDFLAGS	+= -fPIE -pie -s
+include $(BUILD_EXECUTABLE)