gistfile1.txt

...
Compiler for C supports arguments -Wattributes: YES
Compiler for C supports arguments -Wlong-long: YES
Compiler for C supports arguments -Wmissing-field-initializers: YES
Run-time dependency pciaccess found: YES 0.16
Run-time dependency cunit found: NO (tried pkgconfig and cmake)
Run-time dependency valgrind found: NO (tried pkgconfig)
Program rst2man found: NO

meson.build:264:0: ERROR: Program 'rst2man' not found

A full log can be found at /wrkdirs/usr/ports/graphics/libdrm/work/libdrm-2.4.104/_build/meson-logs/meson-log.txt
===>  Script "configure" failed unexpectedly.
Please report the problem to x11@FreeBSD.org [maintainer] and attach the
"/wrkdirs/usr/ports/graphics/libdrm/work/libdrm-2.4.104/_build/meson-logs/meson-log.txt"
including the output of the failure of your make command. Also, it might be
a good idea to provide an overview of all packages installed on your system
(e.g. a /usr/local/sbin/pkg-static info -g -Ea).
*** Error code 1