diff --git a/ANNOUNCE b/ANNOUNCE
index 795045b75..622114f4d 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -83,6 +83,9 @@ Version 1.6.3beta07 [June 6, 2013]
   Deleted set(CMAKE_BUILD_TYPE) block from CMakeLists.txt
   Enclose the prototypes for the simplified write API in
     #ifdef PNG_STDIO_SUPPORTED/#endif
+  Make ARM NEON support work at compile time (not just configure time).
+    This moves the test on __ARM_NEON__ into pngconf.h to avoid issues when
+    using a compiler that compiles for multiple architectures at one time.
 
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diff --git a/CHANGES b/CHANGES
index 2add01c76..738cc8b5a 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4567,6 +4567,9 @@ Version 1.6.3beta07 [June 6, 2013]
   Deleted set(CMAKE_BUILD_TYPE) block from CMakeLists.txt
   Enclose the prototypes for the simplified write API in
     #ifdef PNG_STDIO_SUPPORTED/#endif
+  Make ARM NEON support work at compile time (not just configure time).
+    This moves the test on __ARM_NEON__ into pngconf.h to avoid issues when
+    using a compiler that compiles for multiple architectures at one time.
 
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 (subscription required; visit
diff --git a/configure.ac b/configure.ac
index 86c9b886b..4bf8efff5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -239,11 +239,12 @@ AC_ARG_ENABLE([arm-neon],
       [Enable ARM NEON optimizations: =no/off, check, api, yes/on:]
       [no/off: disable the optimizations; check: use internal checking code]
       [(deprecated and poorly supported); api: disable by default, enable by]
-      [a call to png_set_option; yes/on: turn on unconditionally.]),
+      [a call to png_set_option; yes/on: turn on unconditionally.]
+      [If not specified: determined by the compiler.]),
    [case "$enableval" in
       no|off)
          # disable the default enabling on __ARM_NEON__ systems:
-         AC_DEFINE([PNG_NO_ARM_NEON], [],
+         AC_DEFINE([PNG_ARM_NEON_NOT_SUPPORTED], [],
                    [Disable ARM Neon optimizations])
          # Prevent inclusion of the assembler files below:
          enable_arm_neon=no;;
diff --git a/scripts/pnglibconf.dfa b/scripts/pnglibconf.dfa
index aed476128..ff00b450c 100755
--- a/scripts/pnglibconf.dfa
+++ b/scripts/pnglibconf.dfa
@@ -158,12 +158,6 @@ logunsupported = 1
 @#  endif
 @#endif
 
-# This changes the default for the ARM NEON optimizations according to
-# __ARM_NEON__
-@#ifdef __ARM_NEON__
-@#  define PNG_ARM_NEON_SUPPORTED
-@#endif
-
 # IN DEVELOPMENT
 # These are currently experimental features; define them if you want (NOTE:
 # experimental options must be disabled before they are defined in this file!)
@@ -213,12 +207,15 @@ option SET_OPTION disabled
 # These options are specific to the ARM NEON hardware optimizations:
 #
 # ARM_NEON: the optimization itself
+# ARM_NEON_NOT: disable the optimization even on systems that apparently support
+#               it (where the compiler defines __ARM_NEON__).
 # ARM_NEON_API: allow the optimization to be switched on with png_set_hardware
 # ARM_NEON_CHECK: compile a run-time check to see if Neon extensions are
 #                 supported, this is poorly supported and deprectated - use the
 #                 png_set_hardware API.
 option ARM_NEON disabled,
    sets FILTER_OPTIMIZATIONS png_init_filter_functions_neon
+option ARM_NEON_NOT disabled
 option ARM_NEON_API disabled enables SET_OPTION ARM_NEON
 option ARM_NEON_CHECK disabled enables ARM_NEON