git: bb5a2106555d - stable/14 - config.5: Document CONF_CFLAGS under 'makeoptions'
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Date: Mon, 16 Jun 2025 20:24:44 UTC
The branch stable/14 has been updated by olce: URL: https://cgit.FreeBSD.org/src/commit/?id=bb5a2106555d810bb6a5ec0a80584abf8154cfbd commit bb5a2106555d810bb6a5ec0a80584abf8154cfbd Author: Olivier Certner <olce@FreeBSD.org> AuthorDate: 2025-05-27 07:41:19 +0000 Commit: Olivier Certner <olce@FreeBSD.org> CommitDate: 2025-06-16 20:09:06 +0000 config.5: Document CONF_CFLAGS under 'makeoptions' This variable serves to tweak CFLAGS from the kernel configuration file, easing some custom kernel builds. It was introduced by bde@ in 1999. The description has been kept simple on purpose. It does not completely reflect reality as the build infrastructure actually appends variables to CFLAGS after CONF_CFLAGS has been processed in a few cases. However, these cases do not collide with expected common uses of CONF_CFLAGS, so have not been mentioned. Reviewed by: markj (older version) MFC after: 3 days Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D50544 (cherry picked from commit 1bdf1b8186359d4ea26e26de03e03b7c1543b707) Event: Kitchener-Waterloo Hackathon 202506 --- usr.sbin/config/config.5 | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/usr.sbin/config/config.5 b/usr.sbin/config/config.5 index f77b79a31510..a04ecd4ac0fe 100644 --- a/usr.sbin/config/config.5 +++ b/usr.sbin/config/config.5 @@ -307,11 +307,28 @@ variable is specified, .Ar value is assumed to be the empty string. .Pp +Note that, as the common makefiles overwrite the +.Va CFLAGS +variable after having processed the configuration file, +customizing +.Va CFLAGS +directly via +.Ic makeoptions +is not possible. +Nonetheless, custom compiler flags can be specified using the +.Va CONF_CFLAGS +variable instead. +Its content is appended to +.Va CFLAGS +after the common makefiles have set the latter, allowing to override their +compilation flags. +.Pp Example: .Bd -literal -offset indent -compact makeoptions MYMAKEOPTION="foo" makeoptions MYMAKEOPTION+="bar" makeoptions MYNULLMAKEOPTION +makeoptions CONF_CFLAGS+="-DSOME_CONTROLLING_MACRO" .Ed .\" -------- MAXUSERS -------- .Pp