Don't build the kernel image for cross compiler

Rakefile

@@ -228,7 +228,7 @@ namespace :cross do
       'HOSTCFLAGS' => "-D_UUID_T -D__GETHOSTUUID_H -I#{TMP + 'tools/include'}"
     }
     sh env, 'make', 'rv32_defconfig', chdir: cwd.to_path
-    sh env, 'make', '-j', Etc.nprocessors.to_s, chdir: cwd.to_path
+    # sh env, 'make', '-j', Etc.nprocessors.to_s, chdir: cwd.to_path
     sh env, 'make', 'headers', chdir: cwd.to_path
 
     user_directory = options.sysroot + 'usr'
@@ -298,7 +298,7 @@ namespace :cross do
       "--build=#{options.build}",
       "--host=#{options.build}"
     ]
-    flags = '-O2 -fPIC'
+    flags = '-O2 -fPIC -I/opt/homebrew/opt/flex/include'
     env = {
       'CFLAGS' => flags,
       'CXXFLAGS' => flags,