In Windows 10, when I tried to flash a program to my keyboard through MINGW64, I got an error like this and couldn't flash.

USERNAME@USERPC MINGW64 ~/qmk_firmware
$make lily58:default:avrdude
QMK Firmware 0.8.13
Making Lily58/rev1 with keymap default and target avrdude

make[1]: enters directory '/home/USERNAME/qmk_firmware'
/bin/sh: avr-gcc: command not found
sh: avr-gcc: command not found
sh: avr-gcc: command not found
make[1]: *** [tmk_core/rules.mk:257: gccversion]Error 127
make[1]: exits directory '/home/USERNAME/qmk_firmware'
Make finished with errors
make: *** [Makefile:579: lily58:default:avrdude]Error 1

It seems that avr-gcc is not installed.
It should be installed by running "util/qmk_install.sh".
There should be "avr8-gnu-toolchain" directory in "qmk_utils" directory, which located in the same directory as "qmk_firmware."
But i can't find this directory even though I run the command again.

Failure to make · Issue #4318 · qmk/qmk_firmware
I run make planck/rev5:default and get Making planck/rev5 with keymap default /bin/sh: avr-gcc: command not found sh: avr-gcc: command not found sh: avr-gcc: command not found make: *** [tmk_cor...
GitHub

I carefully reviewed the log, and I found that anti-virus software installed on my PC seems to interfere with the command.
I succeed in installing avr-gcc by run the command after disabling the anti-virus software.

Now I can flash a program.
It's a happy ending!

QMK Firmwareでファームウェアをビルドしようとしたらavr-gccでコケた話 - Qiita
**めっちゃ雑に纏めてます。眠いので許して**# 結論最初から`--recurse-submodules`付きでcloneすればいい話でした((https://docs.qmk.fm/#/newb...
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