minc: read directory names from stdin

This matches `mlist` where it can take directories as arguments or via
stdin.

Closes: #244 [via git-merge-pr]

GNUmakefile

@@ -28,8 +28,8 @@ all: $(ALL) museragent
 $(ALL) : % : %.o
 maddr magrep mdeliver mexport mflag mflow mgenmid mhdr mpick mscan msed mshow \
   msort mthread : blaze822.o mymemmem.o mytimegm.o
-maddr magrep mdeliver mexport mflag mgenmid mhdr mlist mpick mscan msed mseq \
-  mshow msort mthread : seq.o slurp.o mystrverscmp.o
+maddr magrep mdeliver mexport mflag mgenmid mhdr minc mlist mpick mscan msed \
+  mseq mshow msort mthread : seq.o slurp.o mystrverscmp.o
 maddr magrep mflow mhdr mpick mscan mshow : rfc2047.o
 magrep mflow mhdr mshow : rfc2045.o
 mshow : filter.o safe_u8putstr.o rfc2231.o pipeto.o

man/minc.1

@@ -17,6 +17,9 @@ by moving them from
 to
 .Pa cur ,
 and adjusting the filenames.
+If used non-interactively with no specified folders,
+.Nm
+reads directory names from the standard input.
 .Pp
 By default, the new filenames are printed,
 separated by newlines.

minc.c

@@ -74,14 +74,17 @@ usage:
 			exit(1);
 		}
 
-	if (optind == argc)
-		goto usage;
-
 	xpledge("stdio rpath cpath", "");
 
 	status = 0;
-	for (i = optind; i < argc; i++)
-		inc(argv[i]);
+	if (optind == argc) {
+		if (isatty(0))
+			goto usage;
+		blaze822_loop(0, 0, inc);
+	} else {
+		for (i = optind; i < argc; i++)
+			inc(argv[i]);
+	}
 
 	return status;
 }

t/9000-minc.t

@@ -1,7 +1,7 @@
 #!/bin/sh -e
 cd ${0%/*}
 . ./lib.sh
-plan 1
+plan 2
 
 rm -rf test.dir
 mkdir test.dir
@@ -16,4 +16,10 @@ inbox/new/2
 
 check_test 'minc' -eq 2 'minc inbox | wc -l'
 
+while read f; do touch "$f"; done <<!
+inbox/new/3:2,
+inbox/new/4
+!
+
+check_test 'minc stdin' -eq 2 'echo inbox | minc | wc -l'
 )