Add SANITIZE=1 option

Author: kohler

common/rules.mk

@@ -7,6 +7,9 @@ O ?= -O3
 ifeq ($(filter 0 1 2 3 s,$(O)),$(strip $(O)))
 override O := -O$(O)
 endif
+ifeq ($(SANITIZE),1)
+CC += -fsanitize=address -fsanitize=undefined
+endif
 
 # these rules ensure dependencies are created
 DEPCFLAGS = -MD -MF $(DEPSDIR)/$*.d -MP

fundamentals3/addrspace.c

@@ -18,5 +18,7 @@ int main(int argc, char* argv[]) {
     printf("Address of a const local variable\t%p\n", &const_local_ch);
     printf("Address of a heap variable\t\t%p\n", heap_ch);
     printf("Address of main\t\t\t\t%p\n", main);
+
+    free(heap_ch);
     return 0;
 }