Prioritize local headers over additional system includes.

src/Makefile.in

@@ -14,7 +14,7 @@ CFG_INCLUDE=../include
 # DESTDIR=
 
 CC=@CC@
-CFLAGS=@CFLAGS@ @DEFS@ -I $(CFG_INCLUDE) -I $(SRC_INCLUDE)
+CFLAGS=-I $(CFG_INCLUDE) -I $(SRC_INCLUDE) @CFLAGS@ @DEFS@
 LDFLAGS=@LDFLAGS@ @LIBS@
 SOCKETLIBS=@SOCKETLIBS@
 LIBWRAPLIBS=@LIBWRAPLIBS@