--- Portfile.orig	2017-10-07 17:22:23.000000000 -0700
+++ Portfile	2017-10-25 05:33:32.000000000 -0700
@@ -122,6 +122,12 @@
 # ImageMagick uses .la files at runtime to find its coder modules.
 destroot.delete_la_files    no
 
+if {${os.major} < 11} {
+    # ImageMagick requires OpenCL version 1.1,
+    #    which was not introduced until Mac OS X 10.7
+    configure.args-append --disable-opencl
+}
+
 variant graphviz description {Support Graphviz} {
     depends_lib-append      path:bin/dot:graphviz
     configure.args-replace  --without-gvc --with-gvc