Backport upstream patch to fix deprecation warning for CMake < 3.10
introduced with CMake version 3.31.

See-also: https://github.com/naelstrof/slop/commit/6756a334a63dec0cca890d56f67c0042d40c4851
From: Lucio Sauer <watermanpaint@posteo.net>
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.5.0)
+cmake_minimum_required(VERSION 3.11)
 
 project(slop VERSION 7.7 LANGUAGES CXX)
 
@@ -18,7 +18,6 @@ set( BUILD_SHARED_LIBS ON CACHE BOOL "Build all libraries as shared" )
 set( SLOP_OPENGL TRUE CACHE BOOL "To enable or disable OpenGL support." )
 if ( SLOP_OPENGL )
   add_definitions(-DSLOP_OPENGL="True")
-  set(OpenGL_GL_PREFERENCE "GLVND")
 endif()
 
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_SOURCE_DIR}/bin/")
@@ -100,16 +99,12 @@ endif()
 
 target_link_libraries(${EXECUTABLE_NAME} ${LIBRARY_NAME} )
 
-if( CMAKE<3.7 )
-  message( WARNING "CMake version is below 3.7, CMake version >= 3.7 is required for unicode support." )
-else()
-  find_package(ICU COMPONENTS uc)
-  set( SLOP_UNICODE TRUE CACHE BOOL "To enable or disable unicode support." )
-  if ( SLOP_UNICODE AND ICU_FOUND )
-    add_definitions(-DCXXOPTS_USE_UNICODE)
-    include_directories( ${ICU_INCLUDE_DIR} )
-    target_link_libraries(${EXECUTABLE_NAME} ${ICU_UC_LIBRARIES} )
-  endif()
+find_package(ICU COMPONENTS uc)
+set( SLOP_UNICODE TRUE CACHE BOOL "To enable or disable unicode support." )
+if ( SLOP_UNICODE AND ICU_FOUND )
+  add_definitions(-DCXXOPTS_USE_UNICODE)
+  include_directories( ${ICU_INCLUDE_DIR} )
+  target_link_libraries(${EXECUTABLE_NAME} ${ICU_UC_LIBRARIES} )
 endif()
 
 install( TARGETS ${EXECUTABLE_NAME} DESTINATION "${CMAKE_INSTALL_BINDIR}" )
-- 
2.51.0