jhbuild run pkg-config

jhbuild run pkg-config --modversion libxml-2.0 libxslt
Package libxml-2.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `libxml-2.0.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libxml-2.0' found
Package libxslt was not found in the pkg-config search path.
Perhaps you should add the directory containing `libxslt.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libxslt' found