[v2] gcc: Fix wrong order of gcc include paths on musl systems

musl does not use gcc private system headers, however, the path gets
prepended since gcc driver passes -iprefix option to cc1 based on its
installation location. This starts to prefer these headers instead of
musl provided equivalent system headers which is not as per musl's
design. This patch switches prepend to append for musl systems.

Signed-off-by: Khem Raj <raj.khem@gmail.com>
---
v2: Use a runtime check instead of build time check

 meta/recipes-devtools/gcc/gcc-14.1.inc        |  1 +
 ...te-include-paths-on-musl-instead-of-.patch | 36 +++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 meta/recipes-devtools/gcc/gcc/0026-Append-GCC-private-include-paths-on-musl-instead-of-.patch

ignore this one.

On Thu, Jun 27, 2024 at 12:51 AM Khem Raj <raj.khem@gmail.com> wrote:
>
> musl does not use gcc private system headers, however, the path gets
> prepended since gcc driver passes -iprefix option to cc1 based on its
> installation location. This starts to prefer these headers instead of
> musl provided equivalent system headers which is not as per musl's
> design. This patch switches prepend to append for musl systems.
>
> Signed-off-by: Khem Raj <raj.khem@gmail.com>
> ---
> v2: Use a runtime check instead of build time check
>
>  meta/recipes-devtools/gcc/gcc-14.1.inc        |  1 +
>  ...te-include-paths-on-musl-instead-of-.patch | 36 +++++++++++++++++++
>  2 files changed, 37 insertions(+)
>  create mode 100644 meta/recipes-devtools/gcc/gcc/0026-Append-GCC-private-include-paths-on-musl-instead-of-.patch
>
> diff --git a/meta/recipes-devtools/gcc/gcc-14.1.inc b/meta/recipes-devtools/gcc/gcc-14.1.inc
> index b057e570f3b..c4bc4c72664 100644
> --- a/meta/recipes-devtools/gcc/gcc-14.1.inc
> +++ b/meta/recipes-devtools/gcc/gcc-14.1.inc
> @@ -68,6 +68,7 @@ SRC_URI = "${BASEURI} \
>             file://0023-Fix-install-path-of-linux64.h.patch \
>             file://0024-Avoid-hardcoded-build-paths-into-ppc-libgcc.patch \
>             file://0025-gcc-testsuite-tweaks-for-mips-OE.patch \
> +           file://0026-Append-GCC-private-include-paths-on-musl-instead-of-.patch \
>  "
>
>  S = "${TMPDIR}/work-shared/gcc-${PV}-${PR}/${SOURCEDIR}"
> diff --git a/meta/recipes-devtools/gcc/gcc/0026-Append-GCC-private-include-paths-on-musl-instead-of-.patch b/meta/recipes-devtools/gcc/gcc/0026-Append-GCC-private-include-paths-on-musl-instead-of-.patch
> new file mode 100644
> index 00000000000..cbf5083085a
> --- /dev/null
> +++ b/meta/recipes-devtools/gcc/gcc/0026-Append-GCC-private-include-paths-on-musl-instead-of-.patch
> @@ -0,0 +1,36 @@
> +From 636cb6e700856c3d0f8b86ab408032ceeb7e5d2a Mon Sep 17 00:00:00 2001
> +From: Khem Raj <raj.khem@gmail.com>
> +Date: Wed, 5 Jun 2024 22:56:12 -0700
> +Subject: [PATCH] Append GCC private include paths on musl instead of
> + prepending
> +
> +Musl does not need gcc private compiler headers, therefore use them
> +after standard system header search paths.
> +
> +This fixes packages like python builds to detect the musl systems
> +correclty, as it looks for musl specific stuff in stdarg.h system
> +header, which is wrongly picked from gcc private headers in OE
> +
> +Upstream-Status: Submitted [https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115368]
> +Signed-off-by: Khem Raj <raj.khem@gmail.com>
> +---
> + gcc/gcc.cc | 6 +++++-
> + 1 file changed, 5 insertions(+), 1 deletion(-)
> +
> +diff --git a/gcc/gcc.cc b/gcc/gcc.cc
> +index 01968001c44..f0fcaebc3ae 100644
> +--- a/gcc/gcc.cc
> ++++ b/gcc/gcc.cc
> +@@ -6589,7 +6589,11 @@ do_spec_1 (const char *spec, int inswitch, const char *soft_matched_part)
> +
> +             if (gcc_exec_prefix)
> +               {
> +-                do_spec_1 ("-iprefix", 1, NULL);
> ++      if (OPTION_MUSL)
> ++                  do_spec_1 ("-idirafter", 1, NULL);
> ++      else
> ++                  do_spec_1 ("-iprefix", 1, NULL);
> ++
> +                 /* Make this a separate argument.  */
> +                 do_spec_1 (" ", 0, NULL);
> +                 do_spec_1 (gcc_exec_prefix, 1, NULL);