Don't use NEON instructions for non-NEON ARM CPUs

Since NDK r21b NEON instructions are used by default. Explicitly
disable them for non-NEON CPUs.

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

@@ -14,6 +14,10 @@ LOCAL_SRC_FILES := \
 	compression/zlib/zutil.c compression/liblzf/lzf_c.c compression/liblzf/lzf_d.c \
 	GtbProbe.cpp
 
+ifeq ($(TARGET_ARCH_ABI),armeabi-v7a)
+  LOCAL_ARM_NEON := false
+endif
+
 LOCAL_CFLAGS    := \
 	-I $(LOCAL_PATH)/sysport/ -I $(LOCAL_PATH)/compression/ \
 	-I $(LOCAL_PATH)/compression/liblzf/ -I $(LOCAL_PATH)/compression/zlib/ \

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

@@ -13,6 +13,7 @@ CPU_FEATS_SRC_FILES += $(CPU_FEATS)/src/filesystem.c \
 
 ifeq ($(TARGET_ARCH_ABI),armeabi-v7a)
   UTIL_SRC_FILES += $(CPU_FEATS_SRC_FILES) $(CPU_FEATS)/src/cpuinfo_arm.c
+  LOCAL_ARM_NEON := false
 endif
 #ifeq ($(TARGET_ARCH_ABI),arm64-v8a)
 #  UTIL_SRC_FILES += $(CPU_FEATS_SRC_FILES) $(CPU_FEATS)/src/cpuinfo_aarch64.c

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

@@ -2,12 +2,15 @@ LOCAL_PATH := $(call my-dir)
 
 include $(CLEAR_VARS)
 
-
 LOCAL_MODULE    := rtb
 LOCAL_SRC_FILES := \
 	bitBoard.cpp material.cpp moveGen.cpp position.cpp rtb-probe.cpp tbprobe.cpp \
 	RtbProbe.cpp
 
+ifeq ($(TARGET_ARCH_ABI),armeabi-v7a)
+  LOCAL_ARM_NEON := false
+endif
+
 LOCAL_CFLAGS    := --std=c++11 \
 	-I $(LOCAL_PATH)/sysport/ -I -DNDEBUG -Wall
 

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

@@ -10,6 +10,7 @@ SF_SRC_FILES := \
 MY_ARCH_DEF :=
 ifeq ($(TARGET_ARCH_ABI),armeabi-v7a)
   MY_ARCH_DEF += -DUSE_NEON -mthumb -march=armv7-a -mfloat-abi=softfp -mfpu=neon
+  LOCAL_ARM_NEON := true
 endif
 ifeq ($(TARGET_ARCH_ABI),arm64-v8a)
   MY_ARCH_DEF += -DIS_64BIT -DUSE_POPCNT -DUSE_NEON
@@ -28,6 +29,7 @@ include $(LOCAL_PATH)/build_sf.mk
 ifeq ($(TARGET_ARCH_ABI),armeabi-v7a)
   MY_ARCH_DEF := -mthumb -march=armv7-a -mfloat-abi=softfp
   include $(CLEAR_VARS)
+  LOCAL_ARM_NEON  := false
   LOCAL_MODULE    := stockfish_nosimd
   include $(LOCAL_PATH)/build_sf.mk
   stockfish : stockfish_nosimd