Niels De Graef authored Aug 09, 2019 and Jehan committed Aug 09, 2019

The `GIMP_CONFIG_PROP_*` macros do not automatically set
`G_PARAM_STATIC_STRINGS`, which means each property that uses such a
macro does not have this flag set by default (and almost none set it
themselves). By adding `G_PARAM_STATIC_STRINGS` to
`GIMP_CONFIG_PARAM_FLAGS`, we can prevent this from happening, which
should lead to some unnecessary string copies being prevented.