pick up new version of pico_sdk_import.cmake - only really relevant to optimize git download of pico-sdk

Author: kilograham

pico_sdk_import.cmake

@@ -29,11 +29,22 @@ if (NOT PICO_SDK_PATH)
         if (PICO_SDK_FETCH_FROM_GIT_PATH)
             get_filename_component(FETCHCONTENT_BASE_DIR "${PICO_SDK_FETCH_FROM_GIT_PATH}" REALPATH BASE_DIR "${CMAKE_SOURCE_DIR}")
         endif ()
-        FetchContent_Declare(
-                pico_sdk
-                GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
-                GIT_TAG master
-        )
+        # GIT_SUBMODULES_RECURSE was added in 3.17
+        if (${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.17.0")
+            FetchContent_Declare(
+                    pico_sdk
+                    GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                    GIT_TAG master
+                    GIT_SUBMODULES_RECURSE FALSE
+            )
+        else ()
+            FetchContent_Declare(
+                    pico_sdk
+                    GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                    GIT_TAG master
+            )
+        endif ()
+
         if (NOT pico_sdk)
             message("Downloading Raspberry Pi Pico SDK")
             FetchContent_Populate(pico_sdk)