Not opposed to supporting that, but first we need to sort out a few minor issues:

1. is space indeed the path separator? that's a bit surprising, I would have expected a colon between the two variables.

2. as a policy, slibtool does not rely on environment variables, but here are a few alternatives that come to mind, and which could be used alongside one another:

• --system-dlsearch-path=... if provided from the command line, use that argument value.
• --sysroot-relative configuration: which should work nicely for both native builds and cross-compilation. Given --sysroot=/path/to/sysroot, and with --host being either detected or provided, look for /path/to/sysroot/etc/slibtool/[$HOST].conf and get the default library search path from there.
• --hostcfg=... <== similar to the above, but overriding the default path for the configuration file.

Now that we have a working slibtool.m4, it would probably be beneficial to include some LTFLAGS of sorts in its logic. This will result in Makefile having something like LIBTOOL = dlibtool $(LTFLAGS)

1) Yes
2) --system-dlsearch-path= seems like the solution with the least amount of magic to go wrong. Colon-separated list?

2) --system-dlsearch-path= seems like the solution with the least amount of magic to go wrong. Colon-separated list?

--system-dlsearch-path= is certainly going to be the first to be implemented; and yes, just colon-separated lists please, that's how PATH and related environment variables work, and arguably the only safe way to go about things.