Can't install imagemagick on OS X 10.12.3 with homebrew as package manager

[ackerleytng]

I'm seeing

=-=- Processing actions -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=  🐫
[ERROR] The compilation of imagemagick failed at "make".
Processing  1/2: [imagemagick: ocamlfind remove]
#=== ERROR while installing imagemagick.0.34-1 ================================#
# opam-version 1.2.2
# os           darwin
# command      make
# path         /Users/ackerleytng/.opam/4.02.3/build/imagemagick.0.34-1
# compiler     4.02.3
# exit-code    2
# env-file     /Users/ackerleytng/.opam/4.02.3/build/imagemagick.0.34-1/imagemagick-83198-c61e7b.env
# stdout-file  /Users/ackerleytng/.opam/4.02.3/build/imagemagick.0.34-1/imagemagick-83198-c61e7b.out
# stderr-file  /Users/ackerleytng/.opam/4.02.3/build/imagemagick.0.34-1/imagemagick-83198-c61e7b.err
### stdout ###
# ocamlc -c magick.mli
# ocamlc -c magick.ml
# gcc -fPIC -c -I"/Users/ackerleytng/.opam/4.02.3/lib/ocaml" -DMAGICKCORE_HDRI_ENABLE=1 -DMAGICKCORE_QUANTUM_DEPTH=16 -I/usr/local/Cellar/imagemagick/7.0.5-4/include/ImageMagick-7 imagemagick_wrap.c
### stderr ###
# File "magick.ml", line 953, characters 4-22:
# Warning 3: deprecated: String.set
# Use Bytes.set instead.
# imagemagick_wrap.c:60:10: fatal error: 'magick/ImageMagick.h' file not found
# #include <magick/ImageMagick.h>
#          ^
# 1 error generated.
# make: *** [imagemagick_wrap.o] Error 1

imagemagick is already installed using brew:

$ brew install imagemagick
Warning: imagemagick-7.0.5-4 already installed

Perhaps something changed in imagemagick 7?

$ ls /usr/local/Cellar/imagemagick/7.0.5-4/include/ImageMagick-7
Magick++   Magick++.h MagickCore MagickWand

[sagotch]

Looks like #1