SFML: linking against libm

platform/sfml/rules.mk

@@ -4,7 +4,7 @@ SRCS_C += $(wildcard $(sfml_LOCAL_PATH)/platform/*.c)
 SRCS_CPP += $(wildcard $(sfml_LOCAL_PATH)/*.cpp)
 INCLUDE += $(sfml_LOCAL_PATH)/public
 
-LDFLAGS += -lstdc++ -lsfml-window -lsfml-graphics -lsfml-system -lGL
+LDFLAGS += -lstdc++ -lsfml-window -lsfml-graphics -lsfml-system -lGL -lm
 
 CC = gcc
 CPP = g++