If you check out source code from GIT right now, it will not build and I have not found a solution.

But if you add the following contents to a file called Makefile in libbthread-master directory, you can build:

PLATFORM = $(uname -o)
ifneq ($(PLATFORM),Android)
all:
#       mv pt-test.c pt-test
#       cat `ls *.c` > just-pt.c
        g++ -c -o jpt.o just-pt.cc -I.
        ar crs jpt.a jpt.o
clean:
        rm -f *.a *.o
install:

else
all:
install:
clean:

endif