skip isac_neon if neon is not supported

R=andrew@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/39909004

Patch from Mostyn Bramley-Moore <mostynb@opera.com>.

Cr-Commit-Position: refs/heads/master@{#8610}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8610 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_coding/codecs/isac/isacfix.gypi b/webrtc/modules/audio_coding/codecs/isac/isacfix.gypi
index 45a3436..a6a7f97 100644
--- a/webrtc/modules/audio_coding/codecs/isac/isacfix.gypi
+++ b/webrtc/modules/audio_coding/codecs/isac/isacfix.gypi
@@ -81,7 +81,6 @@
           ],
         }],
         ['target_arch=="arm" and arm_version>=7', {
-          'dependencies': [ 'isac_neon', ],
           'sources': [
             'fix/source/lattice_armv7.S',
             'fix/source/pitch_filter_armv6.S',
@@ -90,6 +89,11 @@
             'fix/source/lattice_c.c',
             'fix/source/pitch_filter_c.c',
           ],
+          'conditions': [
+            ['arm_neon==1 or arm_neon_optional==1', {
+              'dependencies': [ 'isac_neon' ],
+            }],
+          ],
         }],
         ['target_arch=="mipsel" and mips_arch_variant!="r6" and android_webview_build==0', {
           'sources': [