Only pass android_toolchain in android builds.

Unbreaks non-android arm builds of openmax.

BUG=563844
R=rtoy@google.com

Review URL: https://codereview.webrtc.org/1486143002 .
diff --git a/dl/BUILD.gn b/dl/BUILD.gn
index 3b2f7b7..5459f48 100644
--- a/dl/BUILD.gn
+++ b/dl/BUILD.gn
@@ -27,12 +27,13 @@
 
   if (current_cpu == "arm" && is_clang) {
     # TODO(hans) Enable integrated-as (crbug.com/124610).
-    rebased_android_toolchain_root =
-        rebase_path(android_toolchain_root, root_build_dir)
-    asmflags = [
-      "-fno-integrated-as",
-      "-B${rebased_android_toolchain_root}/bin",  # Else /usr/bin/as gets picked up.
-    ]
+    asmflags = [ "-fno-integrated-as" ]
+    if (is_android) {
+      rebased_android_toolchain_root =
+          rebase_path(android_toolchain_root, root_build_dir)
+      # Else /usr/bin/as gets picked up.
+      asmflags += [ "-B${rebased_android_toolchain_root}/bin" ]
+    }
   }
 }
 
diff --git a/dl/dl.gyp b/dl/dl.gyp
index 84b844f..2b0826f 100644
--- a/dl/dl.gyp
+++ b/dl/dl.gyp
@@ -21,9 +21,12 @@
         'conditions' : [
           ['clang==1', {
             # TODO(hans) Enable integrated-as (crbug.com/124610).
-            'cflags': [
-              '-fno-integrated-as',
-              '-B<(android_toolchain)',  # Else /usr/bin/as gets picked up.
+            'cflags': [ '-fno-integrated-as' ],
+            'conditions': [
+              ['OS == "android"', {
+                # Else /usr/bin/as gets picked up.
+                'cflags': [ '-B<(android_toolchain)' ],
+              }],
             ],
           }],
           ['arm_neon==1', {