Remove useless header file, add working Makefile and comments

mygrep/Makefile

@@ -0,0 +1,14 @@
+CC = gcc
+CFLAGS = -std=c99 -pedantic -Wall -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_SVID_SOURCE -D_POSIX_C_SOURCE=200809L -g -c
+TARGET = mygrep
+
+all: $(TARGET).c 
+	$(CC) $(CFLAGS) $(TARGET).c
+	$(CC) $(TARGET).o -o $(TARGET)
+
+install:
+	cp $(TARGET) /usr/local/bin/$(TARGET)
+
+clean:
+	$(RM) $(TARGET).o
+	$(RM) $(TARGET)