Adding joinable threads, and gpr_thd_join.
diff --git a/Makefile b/Makefile
index fad9eb2..4e99231 100644
--- a/Makefile
+++ b/Makefile
@@ -2334,6 +2334,7 @@
src/core/support/sync.c \
src/core/support/sync_posix.c \
src/core/support/sync_win32.c \
+ src/core/support/thd.c \
src/core/support/thd_posix.c \
src/core/support/thd_win32.c \
src/core/support/time.c \
@@ -2428,6 +2429,7 @@
$(OBJDIR)/$(CONFIG)/src/core/support/sync.o:
$(OBJDIR)/$(CONFIG)/src/core/support/sync_posix.o:
$(OBJDIR)/$(CONFIG)/src/core/support/sync_win32.o:
+$(OBJDIR)/$(CONFIG)/src/core/support/thd.o:
$(OBJDIR)/$(CONFIG)/src/core/support/thd_posix.o:
$(OBJDIR)/$(CONFIG)/src/core/support/thd_win32.o:
$(OBJDIR)/$(CONFIG)/src/core/support/time.o: