=> Bootstrap dependency digest>=20010302: found digest-20160304
===> Building for re2-20160801
c++ -c -o obj/util/hash.o  -std=c++11 -pthread -Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -I.   -O2 -march=i586 -DNDEBUG util/hash.cc
In file included from util/hash.cc:41:
In file included from ./util/util.h:33:
/usr/include/c++/atomic:537:2: error: <atomic> is not supported on this single threaded system
#error <atomic> is not supported on this single threaded system
 ^
In file included from util/hash.cc:41:
In file included from ./util/util.h:143:
./util/mutex.h:52:11: fatal error: 'pthread.h' file not found
# include <pthread.h>
          ^
2 errors generated.
Makefile:185: recipe for target 'obj/util/hash.o' failed
gmake: *** [obj/util/hash.o] Error 1
*** Error code 2

Stop.
bmake[1]: stopped in /usr/pkgsrc/devel/re2
*** Error code 1

Stop.
bmake: stopped in /usr/pkgsrc/devel/re2