Dne 6.11.2014 v 01:58 Ben Hutchings napsal(a): > gcc 4.8 and later include <stdc-predef.h> by default. In some > versions of eglibc that includes <bits/predefs.h>, but that may be > missing when building with a biarch compiler. Also <stdc-predef.h> > itself could be missing as we are only trying to build a kernel, not > userland. > > The -nostdinc option disables this, though it isn't explicitly > documented. This option is already used when actually building > the kernel, but not by cc-option and other tests. This can result > in silently miscompiling the kernel. > > References: https://bugs.debian.org/717557 > References: https://bugs.debian.org/726861 > Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> > --- > This specific issue appeared and then was fixed in Debian about a year > ago, but it seems like it can also affect cross-builds. > > It may also be worth adding some sort of sanity test, so we stop > immediately if $(cc-option $(empty),broken) yields 'broken'. > > Ben. > > Makefile | 4 +++- > scripts/Kbuild.include | 15 ++++++++------- > 2 files changed, 11 insertions(+), 8 deletions(-) > > diff --git a/Makefile b/Makefile > index ffc1ce2..c0fbf67 100644 > --- a/Makefile > +++ b/Makefile > @@ -619,6 +619,8 @@ endif > # Tell gcc to never replace conditional load with a non-conditional one > KBUILD_CFLAGS += $(call cc-option,--param=allow-store-data-races=0) > > +NOSTDINC_FLAGS += -nostdinc > + > ifdef CONFIG_READABLE_ASM > # Disable optimizations that make assembler listings hard to read. > # reorder blocks reorders the control in the function > @@ -742,7 +744,7 @@ KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions-called-once) > endif > > # arch Makefile may override CC so keep this after arch Makefile is included > -NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include) > +NOSTDINC_FLAGS += -isystem $(shell $(CC) -print-file-name=include) Why not simply move the whole assignment up? Also, there are two cc-option tests and one cc-disable-warning test before the first part assignment. Looks like a result of a mismerge. Michal -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
