diff --git a/configure.ac b/configure.ac
index 4fb0778..930bf50 100644
--- a/configure.ac
+++ b/configure.ac
@@ -283,17 +283,21 @@ AC_ARG_ENABLE([arm-neon],
    [case "$enableval" in
       no|off)
          # disable the default enabling on __ARM_NEON__ systems:
+         AC_DEFINE([PNG_ARM_NEON], [], [ARM NEON support])
          AC_DEFINE([PNG_ARM_NEON_OPT], [0],
                    [Disable ARM Neon optimizations])
          # Prevent inclusion of the assembler files below:
          enable_arm_neon=no;;
       check)
+         AC_DEFINE([PNG_ARM_NEON], [], [ARM NEON support])
          AC_DEFINE([PNG_ARM_NEON_CHECK_SUPPORTED], [],
                    [Check for ARM Neon support at run-time]);;
       api)
+         AC_DEFINE([PNG_ARM_NEON], [], [ARM NEON support])
          AC_DEFINE([PNG_ARM_NEON_API_SUPPORTED], [],
                    [Turn on ARM Neon optimizations at run-time]);;
       yes|on)
+         AC_DEFINE([PNG_ARM_NEON], [], [ARM NEON support])
          AC_DEFINE([PNG_ARM_NEON_OPT], [2],
                    [Enable ARM Neon optimizations])
          AC_MSG_WARN([--enable-arm-neon: please specify 'check' or 'api', if]
diff --git a/pngpriv.h b/pngpriv.h
index 1997503..789206f 100644
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -125,7 +125,7 @@
     * associated assembler code, pass --enable-arm-neon=no to configure
     * or put -DPNG_ARM_NEON_OPT=0 in CPPFLAGS.
     */
-#  if (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
+#  if defined(PNG_ARM_NEON) && (defined(__ARM_NEON__) || defined(__ARM_NEON)) && \
    defined(PNG_ALIGNED_MEMORY_SUPPORTED)
 #     define PNG_ARM_NEON_OPT 2
 #  else