package/zlib-ng: fix build without neon

Fix the following build failure without NEON probably raised since bump
to version 1.9.9-b1 in commit 1f7b12a0b4572d7e763c431a63c22cfb912b8b14
and
https://github.com/zlib-ng/zlib-ng/commit/ec02ecf104e1d3f1836a908a359f20aa93494df5:

In file included from /home/autobuild/autobuild/instance-4/output-1/build/zlib-ng-2.0.6/arch/arm/adler32_neon.c:11:
/home/autobuild/autobuild/instance-4/output-1/host/lib/gcc/arm-buildroot-linux-uclibcgnueabi/10.3.0/include/arm_neon.h:31:2: error: #error "NEON intrinsics not available with the soft-float ABI.  Please use -mfloat-abi=softfp or -mfloat-abi=hard"
   31 | #error "NEON intrinsics not available with the soft-float ABI.  Please use -mfloat-abi=softfp or -mfloat-abi=hard"
      |  ^~~~~

Fixes:
 - http://autobuild.buildroot.org/results/8260762632cde9eb5bc2154084680b5bec034aa6

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/zlib-ng/zlib-ng.mk

@@ -18,9 +18,15 @@ ZLIB_NG_CONF_OPTS += \
 	-DZLIB_COMPAT=1 \
 	-DZLIB_ENABLE_TESTS=OFF
 
-# Enable NEON and ACLE on ARM
+# Enable ACLE on ARM
 ifeq ($(BR2_arm),y)
-ZLIB_NG_CONF_OPTS += -DWITH_ACLE=1 -DWITH_NEON=1
+ZLIB_NG_CONF_OPTS += -DWITH_ACLE=1
+endif
+
+ifeq ($(BR2_ARM_CPU_HAS_NEON)$(BR2_aarch64),y)
+ZLIB_NG_CONF_OPTS += -DWITH_NEON=ON
+else
+ZLIB_NG_CONF_OPTS += -DWITH_NEON=OFF
 endif
 
 ifeq ($(BR2_powerpc_power8),y)