autotools.eclass: don't inject -I${SYSROOT} to aclocal

When -I${SYSROOT} is injected, it'll override the default of -Im4, which
results in trying to install macros to ${SYSROOT} (a sandbox violation)
when they can't be found.

From aclocal(1):
```
       -I DIR add directory to search list for .m4 files

       --install
              copy third-party files to the first -I directory
```

The first directory is normally -Im4 if anything, whereas when injected
(when ${SYSROOT} is defined), it ends up being ${SYSROOT}, not m4 (so
we try to copy macros to somewhere outside of the build directory).

[We could drop this just for > EAPI 7, but I'm not sure there's much
point there either. As Chewi observed in bug 677002, you can't
assume they'll be present in ${SYSROOT} anyway, and frankly,
the cross-compilation (and --root, --sysroot, and so on) situation
is rather bleak for earlier EAPIs, which is why we did all that
work for 7.]

Bug: https://bugs.gentoo.org/710792
Closes: https://bugs.gentoo.org/677002
Closes: https://bugs.gentoo.org/738918
Thanks-to: James Le Cuirot <chewi@gentoo.org>
Signed-off-by: Sam James <sam@gentoo.org>

1 files changed, 1 insertions, 7 deletions

diff --git a/eclass/autotools.eclass b/eclass/autotools.eclass
index 95c92cc6df8c..e2572290f0cb 100644
--- a/eclass/autotools.eclass
+++ b/eclass/autotools.eclass
@@ -1,4 +1,4 @@
-# Copyright 1999-2021 Gentoo Authors
+# Copyright 1999-2022 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 # @ECLASS: autotools.eclass
@@ -666,12 +666,6 @@ autotools_m4sysdir_include() {
 	# First try to use the paths the system integrator has set up.
 	local paths=( $(eval echo ${AT_SYS_M4DIR}) )
 
-	if [[ ${#paths[@]} -eq 0 && -n ${SYSROOT} ]] ; then
-		# If they didn't give us anything, then default to the SYSROOT.
-		# This helps when cross-compiling.
-		local path="${SYSROOT}/usr/share/aclocal"
-		[[ -d ${path} ]] && paths+=( "${path}" )
-	fi
 	_autotools_m4dir_include "${paths[@]}"
 }