improve Makefile

A new line is wrongfully added to empty input when using the line wrap
option.

Makefile

@@ -1,7 +1,7 @@
-CC = gcc
+CC ::= gcc
-CFLAGS = -Og -g -Wall -Wextra -Werror
+CFLAGS ::= -Og -g -Wall -Wextra -Werror
 
-objects = main.o input.o output.o encode.o
+objects ::= $(patsubst %.c, %.o, $(wildcard *.c))
 
 b64 : $(objects)
 	$(CC) -o b64 $(objects)
@@ -12,4 +12,4 @@ main.o output.o : output.h
 
 .PHONY : clean
 clean :
-	rm -f b64 $(objects)
+	-rm -f b64 $(objects)

main.c

@@ -58,7 +58,7 @@ main(int argc, char *argv[])
                 fwrite(obuf, sizeof(*obuf), n, (out) ? out : stdout);
             }
         } else if (wrp) {
-            last = 0;
+            last = '\n';
             while ((n = fread(obuf, sizeof(*obuf), OCTETBUF, (in) ? in : stdin))) {
                 n = encode(obuf, n, sbuf, url);
                 last = printw((out) ? out : stdout, sbuf, n);