Add a config option to link against system or shipped strlcpy

Makefile

@@ -3,7 +3,7 @@
 
 include config.mk
 
-SRC = ii.c strlcpy.c
+SRC = ii.c
 OBJ = $(SRC:.c=.o)
 
 IICFLAGS = -DVERSION=\"$(VERSION)\" -D_DEFAULT_SOURCE $(CFLAGS)
@@ -19,7 +19,7 @@ options:
 .c.o:
 	$(CC) $(IICFLAGS) -c $<
 
-ii: $(OBJ)
+ii: $(OBJ) $(LIBS)
 	$(CC) $(LDFLAGS) -o $@ $(OBJ) $(LIBS)
 
 $(OBJ): arg.h

config.mk

@@ -6,6 +6,9 @@ PREFIX    = /usr/local
 MANPREFIX = ${PREFIX}/share/man
 DOCPREFIX = ${PREFIX}/share/doc
 
-CFLAGS   = -Os
+# on systems which provide strlcpy(3),
+# remove NEED_STRLCPY from CFLAGS and
+# remove strlcpy.o from LIBS
+CFLAGS   = -DNEED_STRLCPY -Os
 LDFLAGS  = -s
-LIBS     =
+LIBS     = strlcpy.o

ii.c

@@ -24,8 +24,9 @@ char *argv0;
 
 #include "arg.h"
 
-#undef strlcpy
+#ifdef NEED_STRLCPY
 size_t strlcpy(char *, const char *, size_t);
+#endif /* NEED_STRLCPY */
 
 #define IRC_CHANNEL_MAX   200
 #define IRC_MSG_MAX       512 /* guaranteed to be <= than PIPE_BUF */