The expected freetype2 version looks incorrect

I have build Freetype 2.9 and:

$ pkg-config.exe --modversion freetype2
2.9

However, fontconfig build fails because it expects freetype2 >= 21.0.15. Am I using some wrong versioning scheme or is this a typo (2.0.15)?

I noticed cairo library says something about the issue (fragment from their's configure):

# We use pkg-config to look for freetype2, but fall back to
# freetype-config if it fails.  We prefer pkg-config, since we can
# then just put freetype2 >= $FREETYPE_MIN_VERSION in
# Requires.private, but at least up to 2003-06-07, there was no
# freetype2.pc in the release.
#
# FreeType versions come in three forms:
#   release (such as 2.1.9)
#   libtool (such as 9.7.3) (returned by freetype-config and pkg-config)
#   platform-specific/soname (such as 6.3.4)
# and they recommend you never use the platform-specific version
# (see docs/VERSION.DLL in freetype2 sources)
#
# Set these as appropriate:

# release number - for information only
FREETYPE_MIN_RELEASE=2.1.9
# libtool-specific version - this is what is checked
FREETYPE_MIN_VERSION=9.7.3

My pkg-config returns release version of freetype. Is this wrong? I can't even find the "libtool" version of my freetype repository.