libpng fails to build on ARMv8

[rmtheis]

./obj/local/arm64-v8a/objs/png/pngrutil.o: In function `png_init_filter_functions':
/home/theis/ocr/tess/tess-two/jni/libpng/pngrutil.c:3942: undefined reference to `png_init_filter_functions_neon'

[steverichey]

Updating to libpng 1.7.0 seems to fix this. see below

[longnguyencmg]

Can you please help to check this error?

java.lang.UnsatisfiedLinkError: dalvik.system.PathClassLoader[DexPathList[[zip file "/data/app/com.halosolutions..../base.apk"],nativeLibraryDirectories=[/data/app/com.halosolutions..../lib/arm64, /vendor/lib64, /system/lib64]]] couldn't find "liblept.so"

[steverichey]

Messing with libpng/Android.mk to ensure that the libpng/arm files are built before the common_SRC_FILES are built seems to do the trick; on a recent attempt, I was unable to use libpng 1.7 to fix the issue.