Disable the integrated assembler on Android when using Clang.

BUILD.gn

diff --git a/BUILD.gn b/BUILD.gn
index c7ee61b..5a429c9 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -49,6 +49,17 @@
     sources = []
     include_dirs = [ "src/include" ]
 
+    if (is_android && is_clang) {
+      # Disable the integrated assembler and use the one shipped with the NDK.
+      import("//build/config/android/config.gni")
+      rebased_android_toolchain_root =
+          rebase_path(android_toolchain_root, root_build_dir)
+      asmflags = [
+        "-fno-integrated-as",
+        "-B${rebased_android_toolchain_root}/bin",
+      ]
+    }
+
     if (is_msan) {
       public_configs = [ ":no_asm_config" ]
     } else if (current_cpu == "x64") {