From 16f611232701d6d370210e6af3a3dac8fafaee5e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Joakim=20Nohlg=C3=A5rd?= <joakim@nohlgard.se>
Date: Thu, 1 Dec 2022 09:47:43 +0100
Subject: [PATCH] scripts/gcc: Add extra include dir with -idirafter
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Fixes Canadian cross builds failing with missing include file 'stdio.h'
when building libstdc++ for a companion libc with system libc set to
LIBC_NONE.

Signed-off-by: Joakim Nohlgård <joakim@nohlgard.se>
---
 scripts/build/cc/gcc.sh | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/scripts/build/cc/gcc.sh b/scripts/build/cc/gcc.sh
index 8cf03cbd..1d7fc065 100644
--- a/scripts/build/cc/gcc.sh
+++ b/scripts/build/cc/gcc.sh
@@ -295,7 +295,6 @@ do_gcc_core_backend() {
                 exec_prefix="${CT_PREFIX_DIR}/${libstdcxx_name}"
             fi
             extra_config+=( "${CT_CC_SYSROOT_ARG[@]}" )
-            extra_config+=( "--with-headers=${header_dir}" )
             extra_user_config=( "${CT_CC_GCC_EXTRA_CONFIG_ARRAY[@]}" )
             log_txt="libstdc++ ${libstdcxx_name} library"
             # to inhibit the libiberty and libgcc tricks later on
@@ -554,6 +553,13 @@ do_gcc_core_backend() {
         fi
     fi
 
+    # Add an extra system include dir if we have one. This is especially useful
+    # when building libstdc++ with a libc other than the system libc (e.g.
+    # picolibc)
+    if [ -n "${header_dir}" ]; then
+        cflags_for_target="${cflags_for_target} -idirafter ${header_dir}"
+    fi
+
     # For non-sysrooted toolchain, GCC doesn't search except at the installation
     # prefix; in core stage we use a temporary installation prefix - but
     # we may have installed something into the final prefix. This is less than ideal:
@@ -1200,6 +1206,13 @@ do_gcc_backend() {
         fi
     fi
 
+    # Add an extra system include dir if we have one. This is especially useful
+    # when building libstdc++ with a libc other than the system libc (e.g.
+    # picolibc)
+    if [ -n "${header_dir}" ]; then
+        cflags_for_target="${cflags_for_target} -idirafter ${header_dir}"
+    fi
+
     # Assume '-O2' by default for building target libraries.
     cflags_for_target="-g -O2 ${cflags_for_target}"