[gimp-help] autogen.sh: fix the last commit.

[Jehan <jehanp src gnome org>]

commit 572223afc398baf794e9763b19db45e0c336585d
Author: Jehan <jehan girinstud io>
Date:   Mon Aug 2 22:55:28 2021 +0200

    autogen.sh: fix the last commit.
    
    --system-acdir replace the system dir for m4. We actually want to *add*
    the local directory to whatever is default instead.

 autogen.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/autogen.sh b/autogen.sh
index 181fb09a1..751c6a7a3 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -91,7 +91,7 @@ if test -z "$ACLOCAL_FLAGS"; then
     done
 fi
 
-$ACLOCAL --system-acdir=m4macros $ACLOCAL_FLAGS
+$ACLOCAL -I m4macros $ACLOCAL_FLAGS
 RC=$?
 if test $RC -ne 0; then
    echo "$ACLOCAL gave errors. Please fix the error conditions and try again."