A makefile and some random fixes

Makefile

@@ -0,0 +1,26 @@
+
+CC 		 = gcc
+CFLAGS 	 = -Wall -pedantic -ansi
+LDFLAGS  = -lm -lgmp
+BUILDDIR = build
+LIBDIR 	 = lib
+
+STRIP	 = strip
+RMDIR	 = rm -fr
+RM 		 = rm -f
+
+p% : p%.c 
+	mkdir -p $(BUILDDIR)
+	$(CC) $(CFLAGS) $(LDFLAGS) $^ -o $(BUILDDIR)/$@
+	$(STRIP) $(BUILDDIR)/$@
+
+p7 : p7.c $(LIBDIR)/prime.o
+p10 : p10.c $(LIBDIR)/prime.o
+p12 : p12.c $(LIBDIR)/prime.o
+
+$(LIBDIR)/%.o : $(LIBDIR)/%.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+clean :
+	$(RMDIR) $(BUILDDIR)
+	$(RM) $(LIBDIR)/*.o