First check the CMake Package Registry for CUnit

This is useful when building CycloneDDS on platforms that provide CMake
configuration for CUnit outside of Conan.

If no configuration is found in the system CMake registry the module
continues as before.

Co-authored-by: Steven! Ragnarök <steven@nuclearsandwich.com>
Signed-off-by: Scott K Logan <logans@cottsay.net>

cmake/Modules/FindCUnit.cmake

@@ -9,6 +9,11 @@
 #
 # SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 #
+find_package(CUnit CONFIG QUIET)
+if(CUnit_FOUND)
+  message(STATUS "Found CUnit via Config file: ${CUnit_DIR}")
+  set(CUNIT_FOUND ${CUnit_FOUND})
+else()
   set(CUNIT_HEADER "CUnit/CUnit.h")
 
   if(CONAN_INCLUDE_DIRS)
@@ -35,6 +40,7 @@ if(CONAN_LIB_DIRS)
   else()
     find_library(CUNIT_LIBRARY cunit)
   endif()
+endif()
 
 include(FindPackageHandleStandardArgs)
 find_package_handle_standard_args(