Can you “un-precious” a configure variable (invers

Question

The AC_ARG_VAR macro declares a variable precious which has certain cache-checking implications.

Some configure macros declare certain variables precious, and I would like to undo that. For example, AC_PROG_CC will declare CFLAGS as precious, and I need to make it non-precious.

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Motivation

Doing this would allow me to modify CFLAGS in a top-level configure and allow sub-package configures to execute without clashing with cached CFLAGS value. See this question for more background.

Answer 1

AC_DEFUN([AX_UNPRECIOUS], [
    m4_define([_AC_PRECIOUS_VARS], m4_bpatsubst(_AC_PRECIOUS_VARS, [$1
], []))
])

AX_UNPRECIOUS([CFLAGS])
AX_UNPRECIOUS([CXXFLAGS])
...