solve the problem of 'sticky' error while in debug mode, plus other things (below) (#2006)

Co-authored-by: Giloo <gildas@localhost>

Author: GillesDuvert

scripts/build_gdl.sh

@@ -89,8 +89,9 @@ if [ ${BUILD_OS} == "Windows" ]; then
     BSDXDR_URL="https://storage.googleapis.com/google-code-archive-downloads/v2/code.google.com/bsd-xdr/bsd-xdr-1.0.0.tar.gz"
     MSYS2_PACKAGES=(
         readline zlib libpng gsl wxWidgets libgd libtiff libgeotiff netcdf hdf4 hdf5 fftw proj msmpi udunits
-        eigen3 eccodes glpk shapelib expat openssl
+        eigen3 eccodes glpk shapelib expat openssl qhull
     )
+# GD: dunno why graphicsmagick has this special treatment????
     #if you add something in MSYS2_PACKAGES_REBUILD you may have to add special lines in main.yml to push the product in /var/cache/pacman/pkg
     MSYS2_PACKAGES_REBUILD=(
         graphicsmagick