libbb: merge mail and uudecode's base64 decoders

function                                             old     new   delta
read_base64                                            -     378    +378
uudecode_main                                        306     315      +9
parse                                                953     958      +5
read_stduu                                           250     254      +4
base64_main                                          217     219      +2
read_base64                                          358       -    -358
decode_base64                                        371       -    -371
------------------------------------------------------------------------------
(add/remove: 2/2 grow/shrink: 4/0 up/down: 398/-729)         Total: -331 bytes

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
diff --git a/mailutils/mime.c b/mailutils/mime.c
index 44c7d02..682cf45 100644
--- a/mailutils/mime.c
+++ b/mailutils/mime.c
@@ -225,7 +225,7 @@
 	// prepare unique string pattern
 	uniq = xasprintf("%%llu.%u.%s", (unsigned)getpid(), safe_gethostname());
 
-//bb_info_msg("PARSE[%s]", terminator);
+//bb_info_msg("PARSE[%s]", uniq);
 
 	while ((line = xmalloc_fgets_str(stdin, "\r\n\r\n")) != NULL) {
 
@@ -306,7 +306,7 @@
 
 			// dump to fp
 			if (0 == strcasecmp(encoding, "base64")) {
-				decode_base64(stdin, fp);
+				read_base64(stdin, fp, '-');
 			} else if (0 != strcasecmp(encoding, "7bit")
 				&& 0 != strcasecmp(encoding, "8bit")
 			) {