Linux对Android源码单独编译时，出现如下错误，跪求指导答啊！
build/core/dex_preopt.mk:47: warning: overriding commands for target `out/target/product/generic/dex_bootjars/system/framework/android.policy_nodex.jar”
build/core/dex_preopt.mk:47: warning: ignoring old commands for target `out/target/product/generic/dex_bootjars/system/framework/android.policy_nodex.jar”
build/core/dex_preopt.mk:47: warning: overriding commands for target `out/target/product/generic/dex_bootjars/system/framework/apache-xml_nodex.jar”
build/core/dex_preopt.mk:47: warning: ignoring old commands for target `out/target/product/generic/dex_bootjars/system/framework/apache-xml_nodex.jar”
build/core/dex_preopt_libart_boot.mk:48: warning: overriding commands for target `out/target/product/generic/system/framework/arm/boot.art”
build/core/dex_preopt_libart_boot.mk:48: warning: ignoring old commands for target `out/target/product/generic/system/framework/arm/boot.art”
build/core/dex_preopt_libart_boot.mk:54: warning: overriding commands for target `out/target/product/generic/dex_bootjars/system/framework/arm/boot.art”
build/core/dex_preopt_libart_boot.mk:54: warning: ignoring old commands for target `out/target/product/generic/dex_bootjars/system/framework/arm/boot.art”
make: *** No rule to make target `out/host/linux-x86/bin/dex2oatd”, needed by `out/target/product/generic/dex_bootjars/system/framework/arm/boot.art”.  Stop.
make: Leaving directory `/home/jiayongqiang/A2_318/android”
#### make failed to build some targets (1 seconds) ####