Explicitly set CMAKE_INSTALL_LIBDIR to lib (#81)

Author: awegrzyn

CMakeLists.txt

@@ -27,6 +27,9 @@ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -pedantic -Wextra")
 # Set fPIC for all targets
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 
+# Set CMAKE_INSTALL_LIBDIR explicitly to lib (to avoid lib64 on CC7)
+set(CMAKE_INSTALL_LIBDIR lib)
+
 # Set the default build type to "RelWithDebInfo"
 if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
   set(CMAKE_BUILD_TYPE "RelWithDebInfo"
@@ -206,10 +209,10 @@ include(GNUInstallDirs)
 # Build targets with install rpath on Mac to dramatically speed up installation
 # https://gitlab.kitware.com/cmake/community/wikis/doc/cmake/RPATH-handling
 set(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
-list(FIND CMAKE_PLATFORM_IMPLICIT_LINK_DIRECTORIES "${CMAKE_INSTALL_PREFIX}/lib" isSystemDir)
+list(FIND CMAKE_PLATFORM_IMPLICIT_LINK_DIRECTORIES "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}" isSystemDir)
 if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
   if("${isSystemDir}" STREQUAL "-1")
-    set(CMAKE_INSTALL_RPATH "@loader_path/../lib")
+    set(CMAKE_INSTALL_RPATH "@loader_path/../${CMAKE_INSTALL_LIBDIR}")
   endif()
   set(CMAKE_BUILD_WITH_INSTALL_RPATH TRUE)
 endif()