stdint.h not found error on compile for OpenCM

[psyclops]

I am seeing the following error on compile. I have tried various different versions of the OpenCM9.04 (1.51, 1.50, 1.42, 1.31) and both Arduino IDE 1.8.19 and 1.8.20 with no change. In case it had anything to do with my code (which used to compile) I tried compiling one of the example programs (read_write_x) and got the same error.

Oddly enough the file stdint.h is in fact in the directory C:\Users[userid]\AppData\Local\Arduino15\packages\OpenCM904\tools\opencm_gcc\5.4.0-2016q2\lib\gcc\arm-none-eabi\5.4.1\include

Arduino: 1.8.19 (Windows 10), Board: "OpenCM9.04 Board, OpenCM Bootloader"

In file included from C:\Users[userid]\AppData\Local\Arduino15\packages\OpenCM904\hardware\OpenCM904\1.3.1\cores\arduino/Arduino.h:23:0,

             from sketch\read_write_x.ino.cpp:1:

c:\users[userid]\appdata\local\arduino15\packages\opencm904\tools\opencm_gcc\5.4.0-2016q2\lib\gcc\arm-none-eabi\5.4.1\include\stdint.h:9:26: fatal error: stdint.h: No such file or directory

compilation terminated.

exit status 1

Error compiling for board OpenCM9.04 Board.

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