Make sure binutils is stripped.

600MB of binutils per arch is a bit much.

Test: file out/.../bin/aarch64-linux-android-ld.gold
Bug: None
Change-Id: I613dfd5f433d0a83269ef4dfcfe98a499f9ba8dc
diff --git a/build.py b/build.py
index 0702465..918f722 100755
--- a/build.py
+++ b/build.py
@@ -122,10 +122,12 @@
     cc = os.path.join(toolchain, 'bin', '{}-gcc'.format(toolchain_prefix))
     cxx = os.path.join(toolchain, 'bin', '{}-g++'.format(toolchain_prefix))
     ar = os.path.join(toolchain, 'bin', '{}-ar'.format(toolchain_prefix))
+    strip = os.path.join(toolchain, 'bin', '{}-strip'.format(toolchain_prefix))
 
     env['AR'] = ar
     env['CC'] = cc
     env['CXX'] = cxx
+    env['STRIP'] = strip
     if m32:
         env['CFLAGS'] = '-m32'
         env['CXXFLAGS'] = '-m32'
@@ -142,7 +144,7 @@
 
 def install(jobs):
     """Installs binutils."""
-    check_call(['make', 'install', '-j', str(jobs)])
+    check_call(['make', 'install-strip', '-j', str(jobs)])
 
 
 def dist(dist_dir, base_dir, package_name):