在编译uboot的时候报如下错误：
unable to execute 'swig': No such file or directory
error: command 'swig' failed with exit status 1
scripts/dtc/pylibfdt/Makefile:26: recipe for target 'scripts/dtc/pylibfdt/_libfdt.so' failed
make[3]: *** [scripts/dtc/pylibfdt/_libfdt.so] Error 1
scripts/Makefile.build:425: recipe for target 'scripts/dtc/pylibfdt' failed
make[2]: *** [scripts/dtc/pylibfdt] Error 2
make[2]: *** 正在等待未完成的任务....
? UPD ? ? include/generated/version_autogenerated.h
? CC ? ? ?arch/arm/lib/asm-offsets.s
? CC ? ? ?lib/asm-offsets.s
scripts/Makefile.build:425: recipe for target 'scripts/dtc' failed
make[1]: *** [scripts/dtc] Error 2
Makefile:494: recipe for target 'scripts' failed
make: *** [scripts] Error 2
make: *** 正在等待未完成的任务....
? CHK ? ? include/generated/asm-offsets.h
? CHK ? ? include/generated/generic-asm-offsets.h
? UPD ? ? include/generated/asm-offsets.h
? UPD ? ? include/generated/generic-asm-offsets.h
应该是缺少依赖库，安装如下软件即可：
sudo apt-get install swig python-dev python3-dev