diff --git a/Makefile b/Makefile
index ddb673e..bea2a28 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,7 @@
 TARGET = Log.o
 TEST   = test
-CFLAGS = -O2 -std=c++11 -Wall -Wextra -pedantic-errors -g
+LOG_USEMUTEX ?= 0
+CFLAGS = -O2 -std=c++11 -Wall -Wextra -pedantic-errors -g -DLOG_USEMUTEX=$(LOG_USEMUTEX)
 
 .PHONY: all clean