From 50042e2ee26ed031063ccca12e5046e2f84d2ce2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Milo=C5=A1=20Komar=C4=8Devi=C4=87?=
 <miloskomarcevic@aim.com>
Date: Wed, 25 Jan 2023 15:47:31 +0100
Subject: [PATCH] Handle relative and absolute paths for pkg-config file

---
 CMakeLists.txt | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 625e78b4..9070afe2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -143,8 +143,17 @@ if (EXIV2_TEAM_PACKAGING)
   include(cmake/packaging.cmake)
 endif()
 
-join_paths(libdir_for_pc_file "\${prefix}" "${CMAKE_INSTALL_LIBDIR}")
-join_paths(includedir_for_pc_file "\${prefix}" "${CMAKE_INSTALL_INCLUDEDIR}")
+# Handle both relative and absolute paths (e.g. NixOS) for a relocatable package
+if(IS_ABSOLUTE "${CMAKE_INSTALL_LIBDIR}")
+    set(libdir_for_pc_file "${CMAKE_INSTALL_LIBDIR}")
+else()
+    join_paths(libdir_for_pc_file "\${exec_prefix}" "${CMAKE_INSTALL_LIBDIR}")
+endif()
+if(IS_ABSOLUTE "${CMAKE_INSTALL_INCLUDEDIR}")
+    set(includedir_for_pc_file "${CMAKE_INSTALL_INCLUDEDIR}")
+else()
+    join_paths(includedir_for_pc_file "\${prefix}" "${CMAKE_INSTALL_INCLUDEDIR}")
+endif()
 configure_file(cmake/exiv2.pc.in exiv2.pc @ONLY)
 install(FILES ${CMAKE_CURRENT_BINARY_DIR}/exiv2.pc DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)