inspired by qhull-2003.1-pkgconfig.patch, available from git://pkgs.fedoraproject.org/qhull
requires making CMake to fill in the gaps via 'configure_file(... @ONLY)'
author: Kenneth Hoste (UGent)
--- qhull/CMakeLists.txt.orig	2015-09-21 15:27:38.424110227 +0200
+++ qhull/CMakeLists.txt	2015-09-21 15:27:06.403494984 +0200
@@ -430,3 +430,9 @@
 install(FILES html/rbox.man          DESTINATION ${MAN_INSTALL_DIR} RENAME rbox.1)
 install(FILES ${doc_FILES}           DESTINATION ${DOC_INSTALL_DIR})
 install(DIRECTORY html/              DESTINATION ${DOC_INSTALL_DIR})
+
+CONFIGURE_FILE(
+  "${CMAKE_CURRENT_SOURCE_DIR}/qhull.pc.in"
+  "${CMAKE_CURRENT_BINARY_DIR}/qhull.pc"
+)
+INSTALL(FILES "${CMAKE_BINARY_DIR}/qhull.pc"  DESTINATION lib/pkgconfig)
--- qhull/qhull.pc.in	1970-01-01 01:00:00.000000000 +0100
+++ qhull/qhull.pc.in	2012-07-08 08:04:07.795336862 +0200
@@ -0,0 +1,11 @@
+prefix=@CMAKE_INSTALL_PREFIX@
+exec_prefix=${prefix}
+includedir=${prefix}/include
+libdir=${prefix}/lib
+
+Name: qhull
+Description: General dimension convex hull library
+Version: @qhull_VERSION2@
+Requires:
+Libs: -L${libdir} -lqhull -lm
+Cflags: -I${includedir}
