Was my Postgres cluster built with the ICU libraries available for Postgres 10 and later?

I wonder if my installation of Postgres 10 Beta 2 has been built to include the new [*International Components for Unicode (ICU)*](http://site.icu-project.org/) collations. For background info, see [*More robust collations with ICU support in PostgreSQL 10*](https://blog.2ndquadrant.com/icu-support-postgresql-10/) by Peter Eisentraut. I used the pg_config utility to detect the build info. When running pg_config --configure I get output where the last line is 'ICU_LIBS=-L/opt/local/Current/lib -licuuc -licudata -licui18n'. ➠ Does this mean I have the ICU libraries installed, or not? >/Library/PostgreSQL/10Beta2/bin/pg_config --configure > >'--with-icu' '--prefix=/mnt/hgfs/pginstaller.pune/server/staging_cache/osx' '--with-ldap' '--with-openssl' '--with-perl' '--with-python' '--with-tcl' '--with-bonjour' '--with-pam' '--enable-thread-safety' '--with-libxml' '--with-uuid=e2fs' '--with-includes=/opt/local/Current/include/libxml2:/opt/local/Current/include:/opt/local/Current/include/security' '--docdir=/mnt/hgfs/pginstaller.pune/server/staging_cache/osx/doc/postgresql' '--with-libxslt' '--with-libedit-preferred' '--with-gssapi' 'CFLAGS=-isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk -mmacosx-version-min=10.8 -arch i386 -arch x86_64 -O2' 'LDFLAGS=-L/opt/local/Current/lib' 'ICU_CFLAGS=-I/opt/local/Current/include' 'ICU_LIBS=-L/opt/local/Current/lib -licuuc -licudata -licui18n' ➠ Is there another way to detect if my Postgres has the ICU collations available? Some way via SQL? When I execute SELECT * FROM pg_collation ;, of the 845 locale names listed, 575 end in -x-icu. Does that happen only if the ICU libraries are in place?