下面是错误提示，是什么原因？
22:09:54 **** Incremental Build of configura
tion Default for project esp_iot_sdk_v1.0.1 ****
make all
make[1]: Entering directory '/cygdrive/c/Users/Administrator/Desktop/esp_iot_sdk_v1.0.1_15_04_24/esp_iot_sdk_v1.0.1/app'
make[2]: Entering directory '/cygdrive/c/Users/Administrator/Desktop/esp_iot_sdk_v1.0.1_15_04_24/esp_iot_sdk_v1.0.1/app/user'
DEPEND: xt-xcc -M -Os -g -O2 -Wpointer-arith -Wundef -Werror -Wl,-EL -fno-inline-functions -nostdlib -mlongcalls -mtext-section-literals -DICACHE_FLASH -I include -I ./ -I ../../include/ets -I ../include -I ../../include -I ../../include/eagle user_sensor.c
/bin/sh: line 1: xt-xcc: command not found
DEPEND: xt-xcc -M -Os -g -O2 -Wpointer-arith -Wundef -Werror -Wl,-EL -fno-inline-functions -nostdlib -mlongcalls -mtext-section-literals -DICACHE_FLASH -I include -I ./ -I ../../include/ets -I ../include -I ../../include -I ../../include/eagle user_light.c
/bin/sh: line 1: xt-xcc: command not found
DEPEND: xt-xcc -M -Os -g -O2 -Wpointer-arith -Wundef -Werror -Wl,-EL -fno-inline-functions -nostdlib -mlongcalls -mtext-section-literals -DICACHE_FLASH -I include -I ./ -I ../../include/ets -I ../include -I ../../include -I ../../include/eagle user_esp_platform.c
/bin/sh: line 1: xt-xcc: command not found
DEPEND: xt-xcc -M -Os -g -O2 -Wpointer-arith -Wundef -Werror -Wl,-EL -fno-inline-functions -nostdlib -mlongcalls -mtext-section-literals -DICACHE_FLASH -I include -I ./ -I ../../include/ets -I ../include -I ../../include -I ../../include/eagle user_devicefind.c
/bin/sh: line 1: xt-xcc: command not found
DEPEND: xt-xcc -M -Os -g -O2 -Wpointer-arith -Wundef -Werror -Wl,-EL -fno-inline-functions -nostdlib -mlongcalls -mtext-section-literals -DICACHE_FLASH -I include -I ./ -I ../../include/ets -I ../include -I ../../include -I ../../include/eagle user_plug.c
/bin/sh: line 1: xt-xcc: command not found
DEPEND: xt-xcc -M -Os -g -O2 -Wpointer-arith -Wundef -Werror -Wl,-EL -fno-inline-functions -nostdlib -mlongcalls -mtext-section-literals -DICACHE_FLASH -I include -I ./ -I ../../include/ets -I ../include -I ../../include -I ../../include/eagle user_main.c
/bin/sh: line 1: xt-xcc: command not found
DEPEND: xt-xcc -M -Os -g -O2 -Wpointer-arith -Wundef -Werror -Wl,-EL -fno-inline-functions -nostdlib -mlongcalls -mtext-section-literals -DICACHE_FLASH -I include -I ./ -I ../../include/ets -I ../include -I ../../include -I ../../include/eagle user_json.c
/bin/sh: line 1: xt-xcc: command not found
DEPEND: xt-xcc -M -Os -g -O2 -Wpointer-arith -Wundef -Werror -Wl,-EL -fno-inline-functions -nostdlib -mlongcalls -mtext-section-literals -DICACHE_FLASH -I include -I ./ -I ../../include/ets -I ../include -I ../../include -I ../../include/eagle user_webserver.c
/bin/sh: line 1: xt-xcc: command not found
DEPEND: xt-xcc -M -Os -g -O2 -Wpointer-arith -Wundef -Werror -Wl,-EL -fno-inline-functions -nostdlib -mlongcalls -mtext-section-literals -DICACHE_FLASH -I include -I ./ -I ../../include/ets -I ../include -I ../../include -I ../../include/eagle user_esp_platform_timer.c
/bin/sh: line 1: xt-xcc: command not found
xt-xcc -Os -g -O2 -Wpointer-arith -Wundef -Werror -Wl,-EL -fno-inline-functions -nostdlib -mlongcalls -mtext-section-literals -DICACHE_FLASH -I include -I ./ -I ../../include/ets -I ../include -I ../../include -I ../../include/eagle -o .output/eagle/debug/obj/user_esp_platform_timer.o -c user_esp_platform_timer.c
make[2]: xt-xcc: Command not found
make[2]: *** [.output/eagle/debug/obj/user_esp_platform_timer.o] Error 127
../../Makefile:280: recipe for target '.output/eagle/debug/obj/user_esp_platform_timer.o' failed
make[2]: Leaving directory '/cygdrive/c/Users/Administrator/Desktop/esp_iot_sdk_v1.0.1_15_04_24/esp_iot_sdk_v1.0.1/app/user'
make[1]: *** [.subdirs] Error 2
../Makefile:266: recipe for target '.subdirs' failed
make[1]: Leaving directory '/cygdrive/c/Users/Administrator/Desktop/esp_iot_sdk_v1.0.1_15_04_24/esp_iot_sdk_v1.0.1/app'
Makefile:266: recipe for target '.subdirs' failed
make: *** [.subdirs] Error 2
