[gimp/wip/Jehan/native-win64-build] Fix some env variables.

[Jehan <jehanp src gnome org>]

commit e26680036075d57b8506f2ace4d82761065158c2
Author: Jehan <jehan girinstud io>
Date:   Sun May 2 19:53:06 2021 +0200

    Fix some env variables.

 build/windows/build-msys2.sh | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/build/windows/build-msys2.sh b/build/windows/build-msys2.sh
index e88995b7ff..24236bc7be 100644
--- a/build/windows/build-msys2.sh
+++ b/build/windows/build-msys2.sh
@@ -50,11 +50,11 @@ export CC="ccache gcc"
 export GIT_DEPTH=1
 export GIMP_PREFIX=`realpath ~/_install`
 export PATH="$GIMP_PREFIX/bin:$PATH"
-export PKG_CONFIG_PATH="${GIMP_PREFIX}/lib/pkgconfig"
-export PKG_CONFIG_PATH="${GIMP_PREFIX}/share/pkgconfig"
+export PKG_CONFIG_PATH="${GIMP_PREFIX}/lib/pkgconfig:$PKG_CONFIG_PATH"
+export PKG_CONFIG_PATH="${GIMP_PREFIX}/share/pkgconfig:$PKG_CONFIG_PATH"
 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/"
+export XDG_DATA_DIRS="$XDG_DATA_DIRS:${GIMP_PREFIX}/share:/mingw64/share/"
 
 git clone --depth=${GIT_DEPTH} https://gitlab.gnome.org/GNOME/babl.git _babl
 git clone --depth=${GIT_DEPTH} https://gitlab.gnome.org/GNOME/gegl.git _gegl