OpenBSD also provides uuid support directly in its libc, same as FreeBSD.

AUTHORS

@@ -125,6 +125,7 @@ The following submitted code, packages or analysis, and deserve special thanks:
   Rafał Bolanowski
   Sunil Joshi
   Misty De Meo
+  Kent R. Spillner
 
 Thanks to the following, who submitted detailed bug reports and excellent
 suggestions:

ChangeLog

@@ -57,6 +57,7 @@
 - Numerous performance improvements. Taskwarrior 2.5.1 is between X% and
   Y% faster than 2.5.0 when running various commands.
 - New formatting specifier 'relative' for columns of Date type was introduced.
+- Improved OpenBSD support (thanks to Kent R. Spillner).
 
 ------ current release ---------------------------
 

src/util.cpp

@@ -204,7 +204,7 @@ int autoComplete (
 // representation is always lowercase anyway.
 // For the implementation details, refer to
 // http://svnweb.freebsd.org/base/head/sys/kern/kern_uuid.c
-#ifdef FREEBSD
+#if defined(FREEBSD) || defined(OPENBSD)
 const std::string uuid ()
 {
   uuid_t id;

src/util.h

@@ -32,7 +32,7 @@
 #include <vector>
 #include <map>
 #include <sys/types.h>
-#ifdef FREEBSD
+#if defined(FREEBSD) || defined(OPENBSD)
 #include <uuid.h>
 #else
 #include <uuid/uuid.h>