where and when did the variable of option in the file of auto/options created?

[Yu Zhou]

a part of file is like that: 

NGX_GOOGLE_PERFTOOLS=NO
NGX_CPP_TEST=NO


NGX_LIBATOMIC=NO


NGX_CPU_CACHE_LINE=


opt=


for option
do

I want to know where and when did the variable of option in the file of auto/options created.

[Yu Zhou]

because of #!/bin/sh. It means the file will Interpreted by bash.
在 2018年4月11日星期三 UTC+8下午9:19:10，Yu Zhou写道：