ARM scramble function is not included in build

[amishutin]

Hi,

I was compiling fdk-aac for aarch64 platfrom and I noticed that ARM version of scramble function is never included in build.
It looks to me that the reason is incorrect preprocessor directives in scramble_arm.h file.

Replacing this line( scramble_arm.h 106):
-#if defined(FUNCTION_scramble)
with
+#if !defined(FUNCTION_scramble)
fixes the issue, and the function is now included in arm build.
But this causes other compilation errors. Assembly code in this function uses r registers, and it can't be compiled for 64-bit architecture.
I replaced r registers with x, this compiles well.
But now the test-encode-decode.c produces failures.
So, the results of generic scramble function and ARM version do not match.

17 failures
encode hash: 7e1784d6c92bfe1aeb9f1bd806443c660a2da036
decode hash: d04dcdcbddb760ce8370ffc4b28d9a14e3b32da5 

It can be reproduced like this(x86_64 Ubuntu):

• set up aarch64 environment
• ./autogen.sh
• mkdir -p build && cd build
• ../configure --prefix=$BUILD_PATH --host=aarch64-linux-gnu --enable-shared=no --enable-static --enable-example
• make -j8 && make install
• export LD_LIBRARY_PATH=/path/to/aarch64-unknown-linux-gnu/sysroot/lib/
• qemu-aarch64-static ./test-encode-decode Sample01_4.wav

There was used aarch64-linux-gnu-gcc compiler.

Is this a bug or was ARM version of scramble function intentionally excluded from build?

Thanks.