I propose to get rid of src/bin/sage-arch-env and $SAGE_LOCAL/etc/sage-64.txt, which is a very specialized mechanism of storing a bit of configuration in SAGE_LOCAL. Instead, SAGE64 should simply be replaced by adding -m64 in $CC or $CFLAGS and maybe setting ABI=64. See #24596.

Since CFLAG64 is only used to support SAGE64, this implies that CFLAG64 is no longer used either.

CC: @dimpase

Component: build

Author: John Palmieri, Jeroen Demeyer

Branch/Commit: 905e4d4

Reviewer: Dima Pasechnik

Issue created by migration from https://trac.sagemath.org/ticket/23733