diff --git a/arch/z80/src/Makefile.sdccl b/arch/z80/src/Makefile.sdccl
index 9b53baa148..629e65fbca 100644
--- a/arch/z80/src/Makefile.sdccl
+++ b/arch/z80/src/Makefile.sdccl
@@ -21,6 +21,9 @@
 # Tools
 # CFLAGS, CPPFLAGS, ASFLAGS, LDFLAGS are set in $(TOPDIR)/Make.defs
 
+ARCH_SRCDIR = $(TOPDIR)$(DELIM)arch$(DELIM)$(CONFIG_ARCH)$(DELIM)src
+
+CFLAGS += ${shell $(INCDIR) "$(CC)" $(ARCH_SRCDIR)$(DELIM)}
 CFLAGS += ${shell $(INCDIR) "$(CC)" $(ARCH_SRCDIR)$(DELIM)chip}
 CFLAGS += ${shell $(INCDIR) "$(CC)" $(ARCH_SRCDIR)$(DELIM)common}
 CFLAGS += ${shell $(INCDIR) "$(CC)" $(TOPDIR)$(DELIM)sched}
diff --git a/tools/incdir.c b/tools/incdir.c
index d2564e6502..8b108dd1e2 100644
--- a/tools/incdir.c
+++ b/tools/incdir.c
@@ -348,6 +348,10 @@ int main(int argc, char **argv, char **envp)
       wintool = true;
 #endif
     }
+  else if (compiler == COMPILER_SDCC)
+    {
+      cmdarg = "-I";
+    }
   else
     {
       cmdarg = (pathtype == SYSTEM_PATH) ? "-isystem" : "-I";