keep the path for pkg-config path if they are absolute

Fixes #62

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e2d4f7df2767a5c1cc1593c2414f0d3df1e6053d..0ae6bdbee38206e23d35a015b5c79eee483b4349 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -104,8 +104,16 @@ install(FILES ${CMAKE_CURRENT_BINARY_DIR}/matroska_export.h DESTINATION ${CMAKE_
 if(NOT DISABLE_PKGCONFIG)
   set(prefix ${CMAKE_INSTALL_PREFIX})
   set(exec_prefix "\$\{prefix\}")
-  set(libdir "\$\{prefix\}/${CMAKE_INSTALL_LIBDIR}")
-  set(includedir "\$\{prefix\}/${CMAKE_INSTALL_INCLUDEDIR}")
+  if (IS_ABSOLUTE ${CMAKE_INSTALL_LIBDIR})
+    set(libdir "${CMAKE_INSTALL_LIBDIR}")
+  else()
+    set(libdir "\$\{prefix\}/${CMAKE_INSTALL_LIBDIR}")
+  endif()
+  if (IS_ABSOLUTE ${CMAKE_INSTALL_INCLUDEDIR})
+    set(includedir "${CMAKE_INSTALL_INCLUDEDIR}")
+  else()
+    set(includedir "\$\{prefix\}/${CMAKE_INSTALL_INCLUDEDIR}")
+  endif()
   set(PACKAGE_VERSION ${PROJECT_VERSION})
   configure_file(libmatroska.pc.in libmatroska.pc @ONLY)
   install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libmatroska.pc DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)