Question about jhbuild

[daedae11 <daedae11 126 com>]

 I follow the intruction at https://developer.gnome.org/jhbuild/2.32/jhbuild.html.

However, when I run jhbuild sanitycheck in shell, the output is:
jhbuild: working directory (/usr/local/_jhbuild) can not be created

My ~/.jhbuildrc file is:
prefix='/usr/local'

What's the matter?
I want to install gobject-introspection by jhbuild. But I don't know how to do it, I'm a new hand. Help please.