[BUILD] Print the number of targets for the current toolchain with cmake

cmake/main.cmake

@@ -52,7 +52,8 @@ function(setup_firmware_target name)
         RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin"
     )
     get_property(targets GLOBAL PROPERTY VALID_TARGETS)
-    set_property(GLOBAL PROPERTY VALID_TARGETS "${targets} ${name}")
+    list(APPEND targets ${name})
+    set_property(GLOBAL PROPERTY VALID_TARGETS "${targets}")
     setup_openocd(${name})
     setup_svd(${name})
 endfunction()
@@ -67,8 +68,11 @@ endfunction()
 function(collect_targets)
     get_property(targets GLOBAL PROPERTY VALID_TARGETS)
     list(SORT targets)
+    list(JOIN targets " " target_names)
     set(list_target_name "targets")
     add_custom_target(${list_target_name}
-        COMMAND cmake -E echo "Valid targets: ${targets}")
+        COMMAND cmake -E echo "Valid targets: ${target_names}")
     exclude_from_all(${list_target_name})
+    list(LENGTH targets target_count)
+    message("-- ${target_count} targets found for toolchain ${TOOLCHAIN}")
 endfunction()