[gimp/wip/Jehan/native-win64-build] build: move the prefix directory to the build dir.

[Jehan <jehanp src gnome org>]

commit 53d12a07ae59d8d287f60b50b0f1b5b8dd05a253
Author: Jehan <jehan girinstud io>
Date:   Wed May 5 00:38:33 2021 +0200

    build: move the prefix directory to the build dir.
    
    This allows to be uploadable as artifacts of the build.

 build/windows/build-msys2.sh | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/build/windows/build-msys2.sh b/build/windows/build-msys2.sh
index 90a66adee5..72a4f0ff41 100644
--- a/build/windows/build-msys2.sh
+++ b/build/windows/build-msys2.sh
@@ -115,3 +115,5 @@ make -j4
 make install
 
 ccache --show-stats
+
+mv "${GIMP_PREFIX}" .