Hi bcardiff,
I’ve got pkg-config too, I’m just lazy with typing so favour pkgconf slightly, sorry 
For some unknown reason the .pc file was yaml-0.1.pc even though the version is 0.2.2. I don’t understand that naming convention.
Anyway, I’ve symlinked it to yaml.pc, now I get:
$ cat /opt/pkg/lib/pkgconfig/yaml.pc
prefix=/opt/pkg
exec_prefix=${prefix}
includedir=${prefix}/include
libdir=${exec_prefix}/lib
Name: LibYAML
Description: Library to parse and emit YAML
Version: 0.2.2
Cflags: -I${includedir}
Libs: -L${libdir} -lyaml
$ pkg-config yaml --libs
-L/opt/pkg/lib -lyaml
$ l /opt/pkg/lib | ag yaml
-rw-r--r-- 1 root 9.5M Feb 14 11:25 libLLVMObjectYAML.a
-rwxr-xr-x 1 root 212K Jan 28 03:03 libyaml-0.2.dylib
-rw-r--r-- 1 root 239K Jan 28 03:03 libyaml.a
lrwxr-xr-x 1 root 17 Jan 28 03:03 libyaml.dylib -> libyaml-0.2.dylib
-rwxr-xr-x 1 root 950 Jan 28 03:03 libyaml.la
Should I perhaps symlink these as yaml.xx etc?
$ shards
dyld: Library not loaded: /opt/crystal/embedded/lib/libyaml-0.2.dylib
Referenced from: /Users/iainb/Library/Frameworks/Crystal.framework/Versions/Current/embedded/bin/shards
Reason: image not found
[1] 17054 abort shards
Crystal itself seems fine though, it’s just stuff in the embedded dir that fails. For instance, I tried it out on a simple program:
$ crystal run 02-Counting-the-number-of-characters.cr
What is the input string?
testing
testing has 7 characters
If anything comes to mind, just let me know, and thanks for taking time on this, much appreciated.
Regards,
iain