[Buildroot] [PATCH 1/2] package/Makefile.in should grab HOST_DIR headers using -isystem instead of -I.
Yann E. MORIN
yann.morin.1998 at free.fr
Mon Jul 25 21:52:58 UTC 2016
David, All,
On 2016-07-25 15:52 -0400, David Raeman spake thusly:
> HOST_CFLAGS includes a search path for HOST_DIR/usr/include using -I. When
> HOST_CFLAGS is used by a package, these flags are passed to the compiler ahead
> of flags passed by the package's internal make system. If a package has a
> header file with the same name as a header file in HOST_DIR, this causes the
> toolchain to prefer the file from the system include directory because its -I
> appears first on the command line. I believe conflicts should prefer the file
^^^
Please, no personal messages like this. Use alternate, neutral
sentences, maybe something like:
In such a case, the package-provided file should take precedence
over any system-installed header.
> provided by the package. This can be accomplished by using -isystem, which is
> more appropriate then -I for system-level include paths.
>
> Real-world example: I need libfdt present in my HOST_DIR to install a patched
> version of QEMU. Meanwhile, the u-boot package provides its own copy of
> libfdt.h that is modified from upstream. If I have libfdt installed into
> HOST_DIR, then host-uboot-tools fails to build because it grabs the libfdt.h
> from the HOST_DIR area instead of using the patched version from its own
> source tree. This patch corrects this issue.
Same here, please rephrase so that the sentences are neutral:
For example, qemu from the Foo repository does not bundle a libfdt,
and will use the system one when installed. However, qemu has a
libfdt.h header, when libfdt installs its own libfdt.h.
> This assumes the -isystem flag is supported by the host compiler.
After discussing with Thomas on IRC, this is virtually the case for all
current gcc versions: even gcc-3.x had it, and it's long been deprecated
now.
> Signed-off-by: David Raeman <draeman at bbn.com>
> ---
> package/Makefile.in | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/package/Makefile.in b/package/Makefile.in
> index afd5d3a..b0ef706 100644
> --- a/package/Makefile.in
> +++ b/package/Makefile.in
> @@ -222,7 +222,7 @@ UNZIP := $(shell which unzip || type -p unzip) -q
>
> APPLY_PATCHES = support/scripts/apply-patches.sh $(if $(QUIET),-s)
>
> -HOST_CPPFLAGS = -I$(HOST_DIR)/usr/include
> +HOST_CPPFLAGS = -isystem $(HOST_DIR)/usr/include
As I was telling Thomas: the idea totally makes sense, but I can't
assess how it would break...
Still, we can't know if we don;t apply it, so:
Acked-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>o
Regards,
Yann E. MORIN.
> HOST_CFLAGS ?= -O2
> HOST_CFLAGS += $(HOST_CPPFLAGS)
> HOST_CXXFLAGS += $(HOST_CFLAGS)
> --
> 2.7.4
>
> _______________________________________________
> buildroot mailing list
> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot
--
.-----------------.--------------------.------------------.--------------------.
| Yann E. MORIN | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software Designer | \ / CAMPAIGN | ___ |
| +33 223 225 172 `------------.-------: X AGAINST | \e/ There is no |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL | v conspiracy. |
'------------------------------^-------^------------------^--------------------'
More information about the buildroot
mailing list