Index: src/Makefile
===================================================================
--- src/Makefile	(revision 0b512a89f69f30c8be4d3d88ab72e83b30ffec00)
+++ src/Makefile	(revision ffc277e3c054a3016b2cfa2ea3b7a295fd2a54c3)
@@ -33,4 +33,7 @@
 	fb/font-8x16.c
 
+# CFLAGS options same for all targets
+CFLAGS+=-nostdinc -I../include -Werror-implicit-function-declaration -Wmissing-prototypes -Werror
+
 ifdef DEBUG_SPINLOCK
 CFLAGS+=-D$(DEBUG_SPINLOCK)
@@ -60,5 +63,5 @@
 
 depend:
-	$(CC) $(CPPFLAGS) -M $(arch_sources) $(sources) >Makefile.depend
+	$(CC) $(CFLAGS) -M $(arch_sources) $(sources) >Makefile.depend
 
 build: kernel.bin boot