build-m5: add missing CROSS_COMPILE parameter

The build could fail with:

...
make: arm-linux-gnueabi-ar: Command not found
...

This was working by change previously because I must have had that
installed on all my dev machines. I wonder how it got through Docker
though. Oh well.

Author: cirosantilli

build-m5

@@ -17,6 +17,7 @@ class Main(common.BuildCliFunction):
             '-j', str(self.env['nproc']), LF,
             '-f', 'Makefile.{}'.format(arch), LF,
             'CC={}'.format(self.env['gcc_path']), LF,
+            'CROSS_COMPILE={}'.format(self.env['toolchain_prefix_dash']), LF,
             'LD={}'.format(self.env['ld_path']), LF,
             'PWD={}'.format(self.env['gem5_m5_source_dir']), LF,
         ]
@@ -31,7 +32,10 @@ class Main(common.BuildCliFunction):
             cwd=self.env['gem5_m5_source_dir'],
         )
         os.makedirs(self.env['out_rootfs_overlay_bin_dir'], exist_ok=True)
-        self.sh.cp(os.path.join(self.env['gem5_m5_source_dir'], 'm5'), self.env['out_rootfs_overlay_bin_dir'])
+        self.sh.cp(
+            os.path.join(self.env['gem5_m5_source_dir'], 'm5'),
+            self.env['out_rootfs_overlay_bin_dir']
+        )
 
     def clean(self):
         self.sh.run_cmd(