diff --git a/tcl-8.6.5-parallel-make-fix.patch b/tcl-8.6.5-parallel-make-fix.patch
new file mode 100644
index 0000000..3b65005
--- /dev/null
+++ b/tcl-8.6.5-parallel-make-fix.patch
@@ -0,0 +1,13 @@
+diff --git a/unix/Makefile.in b/unix/Makefile.in
+index bc73118..9c237ea 100644
+--- a/unix/Makefile.in
++++ b/unix/Makefile.in
+@@ -1357,7 +1357,7 @@ bncore.o: $(TOMMATH_DIR)/bncore.c $(MATHHDRS)
+ bn_reverse.o: $(TOMMATH_DIR)/bn_reverse.c $(MATHHDRS)
+ 	$(CC) -c $(CC_SWITCHES) $(TOMMATH_DIR)/bn_reverse.c
+ 
+-bn_fast_s_mp_mul_digs.o: $(TOMMATH_DIR)/bn_fast_s_mp_mul_digs.c $(MATHHDRS)
++bn_fast_s_mp_mul_digs.o: $(TOMMATH_DIR)/bn_fast_s_mp_mul_digs.c $(MATHHDRS) $(DTRACE_HDR)
+ 	$(CC) -c $(CC_SWITCHES) $(TOMMATH_DIR)/bn_fast_s_mp_mul_digs.c
+ 
+ bn_fast_s_mp_sqr.o: $(TOMMATH_DIR)/bn_fast_s_mp_sqr.c $(MATHHDRS)