diff -urN sdformat-6.0.0.orig/CMakeLists.txt sdformat-6.0.0/CMakeLists.txt

--- sdformat-6.0.0.orig/CMakeLists.txt	2018-01-25 20:43:24.000000000 +0000

+++ sdformat-6.0.0/CMakeLists.txt	2018-11-23 20:04:09.020944630 +0000

@@ -61,6 +61,8 @@

 set (USE_FULL_RPATH OFF CACHE BOOL "Set to true to enable full rpath")

+set (RUBY_LIB_INSTALL_DIR "lib/ruby" CACHE STRING "Installation directory for ruby scripts (relative to CMAKE_INSTALL_PREFIX)")

+

 if (USE_FULL_RPATH)

   # use, i.e. don't skip the full RPATH for the build tree

diff -urN sdformat-6.0.0.orig/src/cmd/CMakeLists.txt sdformat-6.0.0/src/cmd/CMakeLists.txt

--- sdformat-6.0.0.orig/src/cmd/CMakeLists.txt	2018-01-25 20:43:24.000000000 +0000

+++ sdformat-6.0.0/src/cmd/CMakeLists.txt	2018-11-23 20:04:16.367048961 +0000

@@ -14,4 +14,4 @@

     "${CMAKE_CURRENT_BINARY_DIR}/cmdsdformat${SDF_MAJOR_VERSION}.rb" @ONLY)

 # Install the ruby command line library in an unversioned location.

-install(FILES ${CMAKE_CURRENT_BINARY_DIR}/cmdsdformat${SDF_MAJOR_VERSION}.rb DESTINATION lib/ruby/ignition)

+install(FILES ${CMAKE_CURRENT_BINARY_DIR}/cmdsdformat${SDF_MAJOR_VERSION}.rb DESTINATION ${RUBY_LIB_INSTALL_DIR}/ignition)