idf.py: pass correct toolchain prefix to the monitor

tools/cmake/project_description.json.in

@@ -7,8 +7,10 @@
     "app_elf":            "${PROJECT_EXECUTABLE}",
     "app_bin":            "${PROJECT_BIN}",
     "git_revision":       "${IDF_VER}",
+    "target":             "${CONFIG_IDF_TARGET}",
     "phy_data_partition": "${CONFIG_ESP32_PHY_INIT_DATA_IN_PARTITION}",
-    "monitor_baud" : "${CONFIG_ESPTOOLPY_MONITOR_BAUD}",
+    "monitor_baud" :      "${CONFIG_ESPTOOLPY_MONITOR_BAUD}",
+    "monitor_toolprefix": "${CONFIG_SDK_TOOLPREFIX}",
     "config_environment" : {
         "COMPONENT_KCONFIGS" : "${COMPONENT_KCONFIGS}",
         "COMPONENT_KCONFIGS_PROJBUILD" : "${COMPONENT_KCONFIGS_PROJBUILD}"

tools/idf.py

@@ -358,6 +358,7 @@ def monitor(action, ctx, args):
     if args.port is not None:
         monitor_args += ["-p", args.port]
     monitor_args += ["-b", project_desc["monitor_baud"]]
+    monitor_args += ["--toolchain-prefix", project_desc["monitor_toolprefix"]]
     monitor_args += [elf_file]
 
     idf_py = [PYTHON] + get_commandline_options(ctx)  # commands to re-run idf.py