PlatformIO: Append FLASHMODE_* macro (#5813)

Author: ivankravets

tools/platformio-build.py

@@ -97,8 +97,8 @@ def scons_patched_match_splitext(path, suffixes=None):
         "__ets__",
         "ICACHE_FLASH",
         ("ARDUINO", 10805),
-        ("ARDUINO_BOARD", '\\"PLATFORMIO_%s\\"'
-            % env.BoardConfig().id.upper()),
+        ("ARDUINO_BOARD", '\\"PLATFORMIO_%s\\"' % env.BoardConfig().id.upper()),
+        "FLASHMODE_${BOARD_FLASH_MODE.upper()}",
         "LWIP_OPEN_SRC"
     ],