Moving to 10.02.0 the docs (https://ghostscript.readthedocs.io/en/gs10.02.0/News.html) still says:
Mainly due to time constraints, we only support including Tesseract from source included in our release packages, and not linking to Tesseract/Leptonica shared libraries. Whether we add this capability will be largely dependent on community demand for the feature. 

But in Bug 706490 this feature has been introduced I have successfully linked it on FreeBSD against both dependencies from the ports tree.

Please update the documentation.

From the ports check:
===========================================================================
=>> Checking shared library dependencies
 0x0000000000000001 NEEDED               Shared library: [libarchive.so.13]
 0x0000000000000001 NEEDED               Shared library: [libc++.so.1]
 0x0000000000000001 NEEDED               Shared library: [libc.so.7]
 0x0000000000000001 NEEDED               Shared library: [libcups.so.2]
 0x0000000000000001 NEEDED               Shared library: [libcurl.so.4]
 0x0000000000000001 NEEDED               Shared library: [libcxxrt.so.1]
 0x0000000000000001 NEEDED               Shared library: [libdl.so.1]
 0x0000000000000001 NEEDED               Shared library: [libfontconfig.so.1]
 0x0000000000000001 NEEDED               Shared library: [libfreetype.so.6]
 0x0000000000000001 NEEDED               Shared library: [libgcc_s.so.1]
 0x0000000000000001 NEEDED               Shared library: [libgs.so.10]
 0x0000000000000001 NEEDED               Shared library: [libidn.so.12]
 0x0000000000000001 NEEDED               Shared library: [libijs.so.1]
 0x0000000000000001 NEEDED               Shared library: [libjbig2dec.so.0]
 0x0000000000000001 NEEDED               Shared library: [libjpeg.so.8]
 0x0000000000000001 NEEDED               Shared library: [liblcms2.so.2]
 0x0000000000000001 NEEDED               Shared library: [libleptonica.so.5]
 0x0000000000000001 NEEDED               Shared library: [libm.so.5]
 0x0000000000000001 NEEDED               Shared library: [libopenjp2.so.7]
 0x0000000000000001 NEEDED               Shared library: [libpaper.so.1]
 0x0000000000000001 NEEDED               Shared library: [libpng16.so.16]
 0x0000000000000001 NEEDED               Shared library: [libtesseract.so.5]
 0x0000000000000001 NEEDED               Shared library: [libthr.so.3]
 0x0000000000000001 NEEDED               Shared library: [libtiff.so.5]
 0x0000000000000001 NEEDED               Shared library: [libz.so.6]