cmake: make ocv_cmake_dump_vars() case insensitive

cmake/OpenCVUtils.cmake

@@ -2,12 +2,14 @@ include(CMakeParseArguments)
 
 # Debugging function
 function(ocv_cmake_dump_vars)
+  set(VARS "")
+  get_cmake_property(_variableNames VARIABLES)
   cmake_parse_arguments(DUMP "" "TOFILE" "" ${ARGN})
   set(regex "${DUMP_UNPARSED_ARGUMENTS}")
-  get_cmake_property(_variableNames VARIABLES)
-  set(VARS "")
+  string(TOLOWER "${regex}" regex_lower)
   foreach(_variableName ${_variableNames})
-    if(_variableName MATCHES "${regex}")
+    string(TOLOWER "${_variableName}" _variableName_lower)
+    if(_variableName MATCHES "${regex}" OR _variableName_lower MATCHES "${regex_lower}")
       set(VARS "${VARS}${_variableName}=${${_variableName}}\n")
     endif()
   endforeach()