Adds a meson wrap for building json-c where we don't have 0.13, plus some other cleanup for libdrm defines.
Also, apparently json-c intends people to use with -I${prefix}/include/json-c, as that's what their pkg-config and documentation says, so this also swaps over to that. It's also needed for the subproject to work.
Adds a meson wrap for building json-c where we don't have 0.13, plus some other cleanup for libdrm defines.
Also, apparently json-c intends people to use with -I${prefix}/include/json-c, as that's what their pkg-config and documentation says, so this also swaps over to that. It's also needed for the subproject to work.