[BUG] Compilation failed - PATH has no delimter

[jejmule]

Describe the bug
When compiling MARLIN 2.1.2.1 for a MKS Tinybee board, I have a file not found error because the base path has no forward slash :

C:Usersjparent1DocumentsGitHubMarlin-2.1.2.1Marlin/src/HAL/ESP32/FlushableHardwareSerial.h: No such file or directory

To Reproduce
Build Marlin 2.1.2.1 for MKS_TINYBEE board

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
(base) PS C:\Users\jparent1\Documents\GitHub\Marlin-2.1.2.1> echo "done" >"C:\Users\jparent1\AppData\Local\Temp\ipc"
(base) PS C:\Users\jparent1\Documents\GitHub\Marlin-2.1.2.1> platformio run -e mks_tinybee
Processing mks_tinybee (platform: espressif32@2.1.0; board: esp32dev; framework: arduino)
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Verbose mode can be enabled via -v, --verbose option
CONFIGURATION: https://docs.platformio.org/page/boards/espressif32/esp32dev.html
PLATFORM: Espressif 32 (2.1.0) > Espressif ESP32 Dev Module
HARDWARE: ESP32 240MHz, 320KB RAM, 4MB Flash
DEBUG: Current (esp-prog) External (esp-prog, iot-bus-jtag, jlink, minimodule, olimex-arm-usb-ocd, olimex-arm-usb-ocd-h, olimex-arm-usb-tiny-h, olimex-jtag-tiny, tumpa)
PACKAGES:

• framework-arduinoespressif32 @ 3.10004.210126 (1.0.4)
• tool-esptoolpy @ 1.30000.201119 (3.0.0)
• toolchain-xtensa32 @ 2.50200.97 (5.2.0)
  Converting Marlin.ino
  LDF: Library Dependency Finder -> https://bit.ly/configure-pio-ldf
  LDF Modes: Finder ~ chain, Compatibility ~ soft
  Found 32 compatible libraries
  Scanning dependencies...
  Dependency Graph
  |-- U8glib-HAL @ 0.5.2
  |-- AsyncTCP @ 1.1.1
  |-- ESP Async WebServer @ 1.2.3
  |-- ESP3DLib @ 1.0.12
  |-- WebSockets @ 2.3.4
  |-- ESP32SSDP @ 1.1.1
  |-- SPI @ 1.0
  |-- EEPROM @ 1.0.3
  |-- ArduinoOTA @ 1.0
  |-- ESPmDNS @ 1.0
  |-- WiFi @ 1.0
  |-- FS @ 1.0
  |-- SPIFFS @ 1.0
  |-- Wire @ 1.0.1
  Building in release mode
  Compiling .pio\build\mks_tinybee\src\src\inc\Warnings.cpp.o
  Marlin/src/inc/Warnings.cpp:742:4: warning: #warning "Contrast cannot be changed when LCD_CONTRAST_MIN >= LCD_CONTRAST_MAX." [-Wcpp]
  #warning "Contrast cannot be changed when LCD_CONTRAST_MIN >= LCD_CONTRAST_MAX."
  ^
  Marlin/src/inc/Warnings.cpp:753:4: warning: #warning "Your FYSETC/MKS/BTT Mini Panel works best with NEOPIXEL_LED, LED_CONTROL_MENU, LED_USER_PRESET_STARTUP, and LED_COLOR_PRESETS." [-Wcpp]
  #warning "Your FYSETC/MKS/BTT Mini Panel works best with NEOPIXEL_LED, LED_CONTROL_MENU, LED_USER_PRESET_STARTUP, and LED_COLOR_PRESETS."
  Marlin/src/inc/Warnings.cpp:759:4: warning: #warning "Your FYSETC Mini Panel works best with LED_USER_PRESET_STARTUP." [-Wcpp]
  #warning "Your FYSETC Mini Panel works best with LED_USER_PRESET_STARTUP."
  ^
  cc1plus.exe: warning: unrecognized command line option '-Wno-register'
  Compiling .pio\build\mks_tinybee\lib430\ESP3DLib\command.cpp.o
  Compiling .pio\build\mks_tinybee\lib430\ESP3DLib\esp3dlib.cpp.o
  Compiling .pio\build\mks_tinybee\lib430\ESP3DLib\esp3dlibconfig.cpp.o
  Compiling .pio\build\mks_tinybee\lib430\ESP3DLib\espcom.cpp.o
  Compiling .pio\build\mks_tinybee\lib430\ESP3DLib\sd_ESP32.cpp.o
  Compiling .pio\build\mks_tinybee\lib430\ESP3DLib\serial2socket.cpp.o
  Compiling .pio\build\mks_tinybee\lib430\ESP3DLib\web_server.cpp.o
  Compiling .pio\build\mks_tinybee\lib430\ESP3DLib\wificonfig.cpp.o
  .pio/libdeps/mks_tinybee/ESP3DLib/src/espcom.cpp:25:52: fatal error: C:Usersjparent1DocumentsGitHubMarlin-2.1.2.1Marlin/src/HAL/ESP32/FlushableHardwareSerial.h: No such file or directory
  compilation terminated.
  .pio/libdeps/mks_tinybee/ESP3DLib/src/sd_ESP32.cpp:24:38: fatal error: C:Usersjparent1DocumentsGitHubMarlin-2.1.2.1Marlin/src/sd/cardreader.h: No such file or directory
  compilation terminated.
  *** [.pio\build\mks_tinybee\lib430\ESP3DLib\sd_ESP32.cpp.o] Error 1
  *** [.pio\build\mks_tinybee\lib430\ESP3DLib\espcom.cpp.o] Error 1
  .pio/libdeps/mks_tinybee/ESP3DLib/src/command.cpp:40:36: fatal error: C:Usersjparent1DocumentsGitHubMarlin-2.1.2.1Marlin/src/inc/Version.h: No such file or directory
  compilation terminated.
  *** [.pio\build\mks_tinybee\lib430\ESP3DLib\command.cpp.o] Error 1
  ====================================================================================================================================== [FAILED] Took 21.80 seconds ======================================================================================================================================

Environment Status Duration

---

mks_tinybee FAILED 00:00:21.804

Marlin Firmware:

• Marlin Branch/Version:[2.1.2.1]
• Any change done in Marlin code/configuration : Configuration only

ESP3DLib :

• ESP3DLib Branch/Version:[1.0.12
• Web UI Version:[e.g 2.1b14]
• Wifi mode:[e.g. STA]
• Any change done in ESP3DLib code/configuration : none

Board used (please complete the following information):

• BOARD: [MKS_tinybee]
• Flash size: [e.g. default]
• partitions: [e.g. default]

Additional context
Add any other context about the problem here.
Wiring, decoded stack, etc...

[github-actions]

Thank your for submiting, please be sure you followed template or your issue may be dismissed.

[luc-github]

there is a bug in Marlin #68

it is fixed in latest bugfix