From 08bb758b150d6d52258b2a4f783e37298bb42373 Mon Sep 17 00:00:00 2001
From: Stephan Bergmann <sbergman@redhat.com>
Date: Sun, 6 Nov 2022 21:51:40 +0100
Subject: [PATCH] Adapt to llvm-config --src-root dropped from LLVM 16 trunk

...with
<https://github.com/llvm/llvm-project/commit/c061892fcdbdfe46884c54a7a7bfe6df54d1df12>
"[llvm-config] Remove --src-root option", causing

> checking for llvm-config... .../llvm-config
> usage: llvm-config <OPTION>... [<COMPONENT>...]
[...]
> dirname: missing operand
> Try 'dirname --help' for more information.

noise during configure

Change-Id: I0051dd523a3f4cebfdd8b14d8f2e83ba9e5e959b
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/142362
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
---
 configure.ac | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index e079b251b108..b4b9a7a24eb7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -8403,9 +8403,11 @@ if test "$COM_IS_CLANG" = "TRUE"; then
             fi
             # Try if clang is built from source (in which case its includes are not together with llvm includes).
             # src-root is [llvm-toplevel-src-dir]/llvm, clang is [llvm-toplevel-src-dir]/clang
-            clangsrcdir=$(dirname $($LLVM_CONFIG --src-root))
-            if test -n "$clangsrcdir" -a -d "$clangsrcdir" -a -d "$clangsrcdir/clang/include"; then
-                COMPILER_PLUGINS_CXXFLAGS="$COMPILER_PLUGINS_CXXFLAGS -I$clangsrcdir/clang/include"
+            if $LLVM_CONFIG --src-root >/dev/null 2>&1; then
+                clangsrcdir=$(dirname $($LLVM_CONFIG --src-root))
+                if test -n "$clangsrcdir" -a -d "$clangsrcdir" -a -d "$clangsrcdir/clang/include"; then
+                    COMPILER_PLUGINS_CXXFLAGS="$COMPILER_PLUGINS_CXXFLAGS -I$clangsrcdir/clang/include"
+                fi
             fi
             # obj-root is [llvm-toplevel-obj-dir]/, clang is [llvm-toplevel-obj-dir]/tools/clang
             clangobjdir=$($LLVM_CONFIG --obj-root)