Added FEATURE flag, fixed rare segfault

tetris/Makefile

@@ -5,15 +5,15 @@ UNAME_S := Windows
 CXX = cl
 CXXFLAGS = -MD -EHsc
 OBJEXT = obj
-LDFLAGS = 
+LDFLAGS =
 OUTPUTFLAG = -Fo
 else
 UNAME_S := $(shell uname -s)
 CXX ?= g++
-CXXFLAGS = -std=c++14 -Wall -Wextra -pedantic -O2
+CXXFLAGS = -std=c++14 -Wall -Wextra -pedantic -O2 # -DDEBUG -DFEATURE # -g -fsanitize=address
 OBJEXT = o
 LDFLAGS ?= -lSDL2 -lSDL2_image -lSDL2_gfx -lSDL2_ttf -pthread
-OUTPUTFLAG = -o 
+OUTPUTFLAG = -o
 endif
 
 TETRIS_OBJECTS = tetris.${OBJEXT} scenes.${OBJEXT} config.${OBJEXT} functions.${OBJEXT} global_vars.${OBJEXT} custom_classes.${OBJEXT}