--- a/config.make.in
+++ b/config.make.in
@@ -41,8 +41,8 @@
 # DIR.src := $(TOP_SRCDIR_REL)/src
 
 # Project-specific CFLAGS
-CPPFLAGS += -I$(DIR.include) -Isrc
-# ^^^ src is for in-tree sqlite3.h
+CPPFLAGS += -I$(DIR.include) -Iextsrc
+# ^^^ extsrc is for in-tree sqlite3.h
 # -I$(DIR.top)
 # -I$(COMPAT_DIR)/javavm/export -I$(COMPAT_DIR)/tcl-8.6/generic
 ifneq (,$(wildcard $(HOME)/include/*))