Search notes:

/etc/msystem.d/

The directory /etc/msystem.d contains the following files
Each of these files sets and exports the following environment variables:
MSYSTEM_PREFIX
MSYSTEM_CARCH
MSYSTEM_CHOST
MINGW_CHOST
MINGW_PREFIX
MINGW_PACHAGE_PREFIX
One of these files is sourced by /etc/msystem, depending on the value of $MSYSTEM.

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