add a meson option to force hdf5 fallback

meson.build

@@ -17,7 +17,7 @@ cppc = meson.get_compiler('cpp')
 hdf5_dep = cppc.find_library('hdf5', required : false)
 
 # This should be a last resort because I hacked the meson.build for hdf5 together in an afternoon and am not sure if it works correctly ;)
-if not hdf5_dep.found()
+if not hdf5_dep.found() or get_option('force_hdf5_fallback')
   hdf5_proj = subproject('hdf5')
   hdf5_dep = hdf5_proj.get_variable('hdf5_dep')
 endif

meson_options.txt

 option('rng_backend', type : 'combo', choices : ['internal_mersenne', 'stl_mt19937', 'stl_mt19937_64'], description : 'The backend used for the random number generator provided by loadleveller')
+
+option('force_hdf5_fallback', type : 'boolean', value : false,  description : 'Use the hdf5.wrap even if an installed versionwas found.')