[gimp/wip/Jehan/native-win64-build] Is this needed? (cf. wiki)

[Jehan <jehanp src gnome org>]

commit c753e07d50bf217fd9cb2be2a6d6cc1fefbc8750
Author: Jehan <jehan girinstud io>
Date:   Sun May 2 19:45:32 2021 +0200

    Is this needed? (cf. wiki)

 build/windows/build-msys2.sh | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/build/windows/build-msys2.sh b/build/windows/build-msys2.sh
index e1d5e27a7a..e88995b7ff 100644
--- a/build/windows/build-msys2.sh
+++ b/build/windows/build-msys2.sh
@@ -53,6 +53,7 @@ export PATH="$GIMP_PREFIX/bin:$PATH"
 export PKG_CONFIG_PATH="${GIMP_PREFIX}/lib/pkgconfig"
 export PKG_CONFIG_PATH="${GIMP_PREFIX}/share/pkgconfig"
 export LD_LIBRARY_PATH="${GIMP_PREFIX}/lib:${LD_LIBRARY_PATH}"
+export ACLOCAL_FLAGS="-I/c/msys64/mingw64/share/aclocal"
 export XDG_DATA_DIRS="$XDG_DATA_DIRS:${GIMP_PREFIX}/share:/usr/local/share:/usr/share:/mingw64/share/"
 
 git clone --depth=${GIT_DEPTH} https://gitlab.gnome.org/GNOME/babl.git _babl