Revert that change. As Matt Kraai rightly points out,

this is not a bug.  What I was I thinking when I committed
this.  Doh!

libbb/fgets_str.c

@@ -55,7 +55,7 @@ char *fgets_str(FILE *file, const char *terminating_string)
 			break;
 		}
 	}
-	if (idx == 0 || linebuf[0] == '\n') {
+	if (idx == 0) {
 		return NULL;
 	}
 	linebuf[idx] = '\0';