freebsd-skq/share/mk/src.sys.mk
kevans a0b266c31c userland build: replace -fno-common with ${CFCOMMONFLAG}
This change allows any downstream or otherwise consumer to easily override
the new -fno-common default on a temporary basis without having to hack into
src.sys.mk, and also makes it a bit easier to search for these specific
cases where -fno-common must be overridden with -fcommon or else the build
will fail.

The gdb build, the only program requiring -fcommon on head/, is switched
over as an example usage. It will need it on all branches, so this does not
harm future mergability.

MFC after:	3 days
2020-04-10 14:01:07 +00:00

46 lines
1.6 KiB
Makefile

# $FreeBSD$
# Note: This file is also duplicated in the sys/conf/kern.pre.mk so
# it will always grab SRCCONF, even if it isn't being built in-tree
# to preserve historical (and useful) behavior. Changes here need to
# be reflected there so SRCCONF isn't included multiple times.
.if !defined(_WITHOUT_SRCCONF)
# Allow user to configure things that only effect src tree builds.
SRCCONF?= /etc/src.conf
.if !empty(SRCCONF) && \
(exists(${SRCCONF}) || ${SRCCONF} != "/etc/src.conf") && \
!target(_srcconf_included_)
# Validate that the user didn't try setting an env-only variable in
# their src.conf. This benefits from already including bsd.mkopt.mk.
.for var in ${__ENV_ONLY_OPTIONS:O:u}
__presrcconf_${var}:= ${MK_${var}:U-}${WITHOUT_${var}:Uno:Dyes}${WITH_${var}:Uno:Dyes}
.endfor
.sinclude "${SRCCONF}"
_srcconf_included_: .NOTMAIN
# Validate the env-only variables.
.for var in ${__ENV_ONLY_OPTIONS:O:u}
__postrcconf_${var}:= ${MK_${var}:U-}${WITHOUT_${var}:Uno:Dyes}${WITH_${var}:Uno:Dyes}
.if ${__presrcconf_${var}} != ${__postrcconf_${var}}
.error Option ${var} may only be defined in ${SRC_ENV_CONF}, environment, or make argument, not ${SRCCONF}.
.endif
.undef __presrcconf_${var}
.undef __postrcconf_${var}
.endfor
.endif # SRCCONF
.endif
# The following should be removed no earlier than LLVM11 being imported into the
# tree, to ensure we don't regress the build. LLVM11 and GCC10 will switch the
# default over to -fno-common, making this redundant.
CFCOMMONFLAG?= -fno-common
CFLAGS+= ${CFCOMMONFLAG}
# tempting, but bsd.compiler.mk causes problems this early
# probably need to remove dependence on bsd.own.mk
#.include "src.opts.mk"