diff --git a/CMakeLists.txt b/CMakeLists.txt
index b36a8a94..74c6de2e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -195,8 +195,16 @@ set(EZTRACE_LIB_DIR ${CMAKE_INSTALL_FULL_LIBDIR})
 #set(__PPTRACE_BINARY_TYPE "PPTRACE_BINARY_TYPE_BFD")
 #set(abs_top_builddir ${CMAKE_BINARY_DIR})
 
-set(INSTALL_INCLUDEDIR "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_INCLUDEDIR}")
-set(INSTALL_LIBDIR "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
+if(IS_ABSOLUTE ${CMAKE_INSTALL_INCLUDEDIR})
+  set(INSTALL_INCLUDEDIR "${CMAKE_INSTALL_INCLUDEDIR}")
+else()
+  set(INSTALL_INCLUDEDIR "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_INCLUDEDIR}")
+endif()
+if(IS_ABSOLUTE ${CMAKE_INSTALL_LIBDIR})
+  set(INSTALL_LIBDIR "${CMAKE_INSTALL_LIBDIR}")
+else()
+  set(INSTALL_LIBDIR "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
+endif()
 set(INSTALL_PKGCONFIG_DIR "${CMAKE_INSTALL_LIBDIR}/pkgconfig")
 
 # Subdirectory