Can't build from source locally

[suntong]

I

• pre-built vips locally
• get the bimg source into /go/src/github.com/h2non/bimg, and under it,
• do go build -v .

and this is what I'm getting:

$ go build -v .
github.com/h2non/bimg
# pkg-config --cflags  -- vips vips vips vips
Package vips was not found in the pkg-config search path.
Perhaps you should add the directory containing `vips.pc'
to the PKG_CONFIG_PATH environment variable
No package 'vips' found
Package vips was not found in the pkg-config search path.
Perhaps you should add the directory containing `vips.pc'
to the PKG_CONFIG_PATH environment variable
No package 'vips' found
Package vips was not found in the pkg-config search path.
Perhaps you should add the directory containing `vips.pc'
to the PKG_CONFIG_PATH environment variable
No package 'vips' found
Package vips was not found in the pkg-config search path.
Perhaps you should add the directory containing `vips.pc'
to the PKG_CONFIG_PATH environment variable
No package 'vips' found
pkg-config: exit status 1