added makefile to compile all examples in recursivity

source_codes/recursivity/Makefile

+CC:=gcc
+SAN:=-fsanitize=address
+CFLAGS:=-Wall -Wextra -pedantic -g $(SAN)
+LDFLAGS:=-lm $(SAN)
+
+EXECS := $(shell find . -type f -iname '*.c' | sed 's/\.c//g')
+
+all: $(EXECS)
+
+$(EXECS): %: %.c
+	# @echo $<
+	$(CC) $(CFLAGS) -o $@ $< $(LDFLAGS)
+
+.PHONY: clean
+
+clean:
+	rm -f *.o $(EXECS)
+