File Catch2-pkgconfig-install-destdir.patch of Package Catch2

From 7cad6d75390668ad2b6bec8432a2e408a992e1bf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Ho=C5=99e=C5=88ovsk=C3=BD?=
 <martin.horenovsky@gmail.com>
Date: Sat, 9 Aug 2025 23:05:08 +0200
Subject: [PATCH] Handle DESTDIR env var when generating pkgconfig files

Having the ability to configure the installation path at config
time, and the ability to change the prefix at install time is not
enough, apparently people also use env var to redirect them instead.

Closes #3006
---
 CMakeLists.txt | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4b4e4f58c2..33377f5d34 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -198,14 +198,14 @@ if(NOT_SUBPROJECT)
          set(lib_name "$<TARGET_FILE_BASE_NAME:Catch2>")
          configure_file(
            "${impl_pc_file}"
-           "${CMAKE_INSTALL_PREFIX}/${install_pkgconfdir}/catch2.pc"
+           "$ENV{DESTDIR}/${CMAKE_INSTALL_PREFIX}/${install_pkgconfdir}/catch2.pc"
            @ONLY
          )
 
          set(lib_name "$<TARGET_FILE_BASE_NAME:Catch2WithMain>")
          configure_file(
            "${main_pc_file}"
-           "${CMAKE_INSTALL_PREFIX}/${install_pkgconfdir}/catch2-with-main.pc"
+           "$ENV{DESTDIR}/${CMAKE_INSTALL_PREFIX}/${install_pkgconfdir}/catch2-with-main.pc"
            @ONLY
          )
        ]]