Avoid hard-coding libdir in sdl2-config This makes the -dev package multiarch co-installable, allowing compilation of SDL programs for more than one architecture on the same system.
This is not an upstreamable change, since it relies on Debian-specific assumptions:
* we are installing the library into a directory on the linker's default search path * static linking is done with at least one of: - $DEB_HOST_MULTIARCH set, or - $PKG_CONFIG set to the host architecture pkg-config, or - $CC set to a compiler for the host architecture that supports the -print-multiarch argument (which Debian's gcc and clang do)
Adapted from an earlier patch by Gianfranco Costamagna.
