cmake: add missing HAVE_NEON to config_auto.h

cmake/Configure.cmake

@@ -118,6 +118,7 @@ file(APPEND ${AUTOCONFIG_SRC} "
 #cmakedefine FAST_FLOAT ${FAST_FLOAT}
 #cmakedefine DISABLED_LEGACY_ENGINE ${DISABLED_LEGACY_ENGINE}
 #cmakedefine HAVE_TIFFIO_H ${HAVE_TIFFIO_H}
+#cmakedefine HAVE_NEON ${HAVE_NEON}
 #cmakedefine HAVE_LIBARCHIVE ${HAVE_LIBARCHIVE}
 #cmakedefine HAVE_LIBCURL ${HAVE_LIBCURL}
 #cmakedefine USE_OPENCL ${USE_OPENCL}