std.Build: Remove unused `c_std` field

This field has not been referenced by compile steps since
e76ce2c1d0d3988359267fd3030a81a52ec99f3f, all the way back in 2019.
To specify the language standard, pass `-std=[value]` as a regular
C flag instead.
09f1bbe11bCarl Åstholm committed on 4/7/2024, 11:06:15 PM· committed by Andrew Kelleyparent05126fc
2 files changedLine totals unavailable