retry install 3 times

Author: ladyada

build_platform.py

@@ -229,7 +229,13 @@ def install_platform(fqbn, full_platform_name=None):
         install_platform("arduino:avr", full_platform_name)
     if full_platform_name[2] is not None:
         manually_install_esp32_bsp(full_platform_name[2]) # build esp32 bsp from desired source and branch
-    if os.system("arduino-cli core install "+fqbn+" --additional-urls "+BSP_URLS+" > /dev/null") != 0:
+    for retry in range(0, 3):
+        if os.system("arduino-cli core install "+fqbn+" --additional-urls "+BSP_URLS+" > /dev/null") == 0:
+            break
+        print("...retrying...", end=" ")
+        time.sleep(10) # wait 10 seconds then try again?
+    else:
+        # tried 3 times to no avail
         ColorPrint.print_fail("FAILED to install "+fqbn)
         exit(-1)
     ColorPrint.print_pass(CHECK)