Don't default to gold for aarch64.

Test: ./build.py --arch arm64 --host linux
Bug: https://issuetracker.google.com/70838247
Change-Id: I70506b9b12d2d904e109536a01276feb7582adc5
diff --git a/build.py b/build.py
index 840ba56..da47824 100755
--- a/build.py
+++ b/build.py
@@ -82,7 +82,6 @@
         os.path.join(src_dir, 'configure'),
         '--target={}'.format(ndk.abis.arch_to_triple(arch)),
         '--host={}'.format(configure_host),
-        '--enable-gold=default',
         '--enable-initfini-array',
         '--enable-plugins',
         '--with-sysroot={}'.format(sysroot),
@@ -91,6 +90,11 @@
 
     if arch == 'arm64':
         configure_args.append('--enable-fix-cortex-a53-835769')
+        configure_args.append('--enable-gold')
+    else:
+        # Gold for aarch64 currently emits broken debug info.
+        # https://issuetracker.google.com/70838247
+        configure_args.append('--enable-gold=default')
 
     if not is_windows:
         # Multithreaded linking is implemented with pthreads, which we