Fix uninstall target for cmake > 3.25

execute_process and exce_program were changed in cmake 3.26 to run
only at configure time, breaking cmake_uninstall.cmake. The recommened
replacement is add_custom_target and add_custom_commsnd, but there's
no way to run a loop in either of those so this commit replaces
cmake_uninstall.cmake with cmake_uninstall.sh. This works on Microsoft
Windows beacuse at present we have to build on Windows in a MSYS2
shell. If at some point we gain the ability to build in a straight
Windows environment then we'll need a Windows CMD equivalent.

CMakeLists.txt

@@ -958,12 +958,12 @@ add_custom_target(distcheck DEPENDS dist
 
 # uninstall target
 configure_file(
-        "${CMAKE_SOURCE_DIR}/cmake/cmake_uninstall.cmake.in"
-        "${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake"
+        "${CMAKE_SOURCE_DIR}/cmake/cmake_uninstall.sh.in"
+        "${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.sh"
         @ONLY)
 
 add_custom_target(uninstall
-        COMMAND ${CMAKE_COMMAND} -P ${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake)
+        COMMAND /bin/sh ${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.sh)
 
 set(_MODULES gnc-core-utils gnc-engine gnc-app-utils gnc-module gnc-locale-tax gnc-backend-xml-utils gnucash-guile)
 

cmake/cmake_uninstall.cmake.in

@@ -1,23 +0,0 @@
-# This is taken from https://cmake.org/Wiki/CMake_FAQ#Can_I_do_.22make_uninstall.22_with_CMake.3F
-
-if(NOT EXISTS "@CMAKE_CURRENT_BINARY_DIR@/install_manifest.txt")
-  message(FATAL_ERROR "Cannot find install manifest: @CMAKE_CURRENT_BINARY_DIR@/install_manifest.txt")
-endif()
-
-file(READ "@CMAKE_CURRENT_BINARY_DIR@/install_manifest.txt" files)
-string(REGEX REPLACE "\n" ";" files "${files}")
-foreach(file ${files})
-  message(STATUS "Uninstalling $ENV{DESTDIR}${file}")
-  if(IS_SYMLINK "$ENV{DESTDIR}${file}" OR EXISTS "$ENV{DESTDIR}${file}")
-    execute_process(
-      COMMAND ${CMAKE_COMMAND} -E remove \"$ENV{DESTDIR}${file}\"
-      OUTPUT_VARIABLE rm_out
-      RESULT_VARIABLE rm_retval
-      )
-    if(NOT "${rm_retval}" STREQUAL 0)
-      message(FATAL_ERROR "Problem when removing $ENV{DESTDIR}${file}")
-    endif()
-  else()
-    message(STATUS "File $ENV{DESTDIR}${file} does not exist.")
-  endif()
-endforeach(file)

cmake/cmake_uninstall.sh.in

@@ -0,0 +1,13 @@
+#!/bin/sh
+if [ ! -s install_manifest.txt ]; then
+    echo "Error: No install manifest."
+fi
+while IFS= read -r filename; do
+    if [ -e $filename ]; then
+        echo "--Uninstalling $filename"
+        rm $filename
+    else
+        echo "--$filename not found"
+    fi
+done<install_manifest.txt
+