freebsd-dev/config/always-no-unused-but-set-variable.m4
Prakash Surya e89236fd28 In autoconf v2.68, AC_LANG_PROGRAM must be quoted
This change updates the AC_LANG_PROGRAM autoconf macro invocations to be
wrapped in quotes. As of autoconf version 2.68, the quotes are necessary
to prevent warnings from appearing. Specifically, the autoconf v2.68
Forward Porting Notes specifies:

    It is important to note that you need to ensure that the call to
    AC_LANG_SOURCE is quoted and not expanded, otherwise that will
    cause the warning to appear nonetheless.

Finally, because of the additional quoting we can drop the extra
quotas used by the ZFS_AC_CONFIG_USER_STACK_GUARD autoconf check.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #464
2011-11-28 11:16:33 -08:00

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dnl #
dnl # Check if gcc supports -Wno-unused-but-set-variable option.
dnl #
dnl # We actually invoke gcc with the -Wunused-but-set-variable option
dnl # and infer the 'no-' version does or doesn't exist based upon
dnl # the results. This is required because when checking any of
dnl # no- prefixed options gcc always returns success.
dnl #
AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_NO_UNUSED_BUT_SET_VARIABLE], [
AC_MSG_CHECKING([for -Wno-unused-but-set-variable support])
saved_flags="$CFLAGS"
CFLAGS="$CFLAGS -Wunused-but-set-variable"
AC_RUN_IFELSE([AC_LANG_PROGRAM([], [])],
[
NO_UNUSED_BUT_SET_VARIABLE=-Wno-unused-but-set-variable
AC_MSG_RESULT([yes])
],
[
NO_UNUSED_BUT_SET_VARIABLE=
AC_MSG_RESULT([no])
])
CFLAGS="$saved_flags"
AC_SUBST([NO_UNUSED_BUT_SET_VARIABLE])
])