56e4e9e197
`NO_DEFAULT_PATH` was added in 565eb6b6fd3e6b2c9275490c3c07e585b0942a92. However this breaks Nixpkgs/NixOS, which installs everything to separate prefixes and adds compiler flags to supply them. This commit removes `NO_DEFAULT_PATH`. Instead, it looks for a header file specific to SDL 2.0 and not in SDL 1.2.