std::mutex is not available

[Insomniac80]

Basic Infos

• [X] This issue complies with the issue POLICY doc.
• [X] I have read the documentation at readthedocs and the issue is not addressed there.
• [X] I have tested that the issue is present in current master branch (aka latest git).
• [X] I have searched the issue tracker for a similar issue.
• [X] If there is a stack dump, I have decoded it.
• [X] I have filled out all fields below.

Platform

• Hardware: ESP-12F
• Core Version: PIO Core 6.1.6
• Development Env: PlatformIO
• Operating System: Windows

Settings in IDE

• Module: WeMos D1 R2 and mini /
• Flash Mode: dio
• Flash Size: 4MB
• lwip Variant: v1.4
• Reset Method: ck
• Flash Frequency: [40Mhz]
• CPU Frequency: 80Mhz
• Upload Using: SERIAL
• Upload Speed: 115200

Problem Description

std::mutex is not available. Have set up a Win10 VM and fresh installed VS Code and PIO to ensure it is not related to one of my libraries or such. Still persists.

MCVE Sketch

main.cpp:

#include <Arduino.h>

#include <mutex>

using std::mutex;

void setup() {}

void loop() {}

platformio.ini:

[env:d1_mini]
platform = espressif8266
board = d1_mini
framework = arduino

Output

src\main.cpp:5:12: error: 'mutex' has not been declared in 'std'
    5 | using std::mutex;
      |            ^~~~~
*** [.pio\build\d1_mini\src\main.cpp.o] Error 1