diff --git a/Makefile b/Makefile
index 70fe875..d95da26 100644
--- a/Makefile
+++ b/Makefile
@@ -1,20 +1,20 @@
 CC=gcc
-CFLAGS=-Wall -Werror -pthread -O3  
+CFLAGS=-Wall -Werror -pthread -O3 -lm 
 LDFLAGS=
 
 default: inexact
 
 windows: CC=x86_64-w64-mingw32-gcc 
-windows: CFLAGS=-Wall -Werror -pthread -O3 
+windows: CFLAGS=-Wall -Werror -pthread -O3 -lm 
 windows: LDFLAGS=
 windows: inexact
 
 windows-debug: CC=x86_64-w64-mingw32-gcc 
-windows-debug: CFLAGS=-Wall -Werror -pthread -O3 -g
+windows-debug: CFLAGS=-Wall -Werror -pthread -O3 -g -lm
 windows-debug: LDFLAGS=
 windows-debug: inexact
 
-debug: CFLAGS=-Wall -Werror -pthread -O3 -g
+debug: CFLAGS=-Wall -Werror -pthread -O3 -g -lm
 debug: LDFLAGS=
 debug: inexact