u-boot failed to build

I am following this guide to create an bootable SD card:
https://eewiki.net/display/linuxonarm/BeagleBone+Black#BeagleBoneBlack-Bootloader:U-Boot

I encounter an error here: make ARCH=arm CROSS_COMPILE=${CC}
My terminal throws this error:

After removing the u-boot folder and follow the steps again, everything works fine. Any idea how that error is thrown anyways?

Hi,

Don’t know if this is your issue but...

How are you generating the .config file? When I build u-boot for the X15, I typically do a distclean, call another make command to generate the correct .config file from the appropriate defconfig , and then throw the command to build u-boot.