Linux u-boot 编译时出现 make: *** [tools] Error: 2

在u-boot编译时输入make指令，出现如下信息：

foreach directory in tools; examples and standalone applications; api; arm-based CPU; arm920t

make -C $dir _depend ; done

引用编号[1]: 切换至存储位置 /home/DHH_Linux/development_board/fl2440_development/bootloader/u-boot-2010.09/tools

make[1]: Nothing to be done for `_depend'.

在Linux系统中运行make[1]命令时会退出位于/home/DHH_Linux/development_board/fl2440_development/bootloader/u-boot-2010.09/tools目录下的相关工作流程

make[1]: Entering directory `/home/DHH_Linux/development_board/fl2440_development/bootloader/u-boot-2010.09/examples/standalone'

make[1]: Nothing to be done for `_depend'.

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