brctl: eliminate stray data object

brctl: use constant fd to reduce parameter passing
runsvdir: do not use data/bss
od: reuse bb_argv_dash
last: do not go into endless loop on read error
mount: make it not fail scripts/find_bad_common_bufsiz check
dc: add INIT_G() (no-op for dc, but we want uniform usage of "G trick")

function                                             old     new   delta
runsvdir_main                                       1646    1672     +26
set_pgrp                                               1       -      -1
exitsoon                                               1       -      -1
check                                                679     678      -1
svnum                                                  4       -      -4
svdir                                                  4       -      -4
sv                                                     4       -      -4
stamplog                                               4       -      -4
rploglen                                               4       -      -4
rplog                                                  4       -      -4
mount_main                                           995     988      -7
static.default_file_list                               8       -      -8
pfd                                                    8       -      -8
logpipe                                                8       -      -8
static.info                                           20       -     -20
brctl_main                                           767     739     -28
------------------------------------------------------------------------------
(add/remove: 0/12 grow/shrink: 1/3 up/down: 26/-106)          Total: -80 bytes
   text    data     bss     dec     hex filename
 793327     662    7412  801401   c3a79 busybox_old
 793329     641    7372  801342   c3a3e busybox_unstripped

1 files changed, 30 insertions, 11 deletions

diff --git a/runit/runsvdir.c b/runit/runsvdir.c
index bca5c901c..32e4764d1 100644
--- a/runit/runsvdir.c
+++ b/runit/runsvdir.c
@@ -42,17 +42,34 @@ struct service {
 	smallint isgone;
 };
 
-static struct service *sv;
-static char *svdir;
-static int svnum;
-static char *rplog;
-static int rploglen;
-static struct fd_pair logpipe;
-static struct pollfd pfd[1];
-static unsigned stamplog;
-static smallint check = 1;
-static smallint exitsoon;
-static smallint set_pgrp;
+struct globals {
+	struct service *sv;
+	char *svdir;
+	char *rplog;
+	int svnum;
+	int rploglen;
+	struct fd_pair logpipe;
+	struct pollfd pfd[1];
+	unsigned stamplog;
+	smallint check; /* = 1; */
+	smallint exitsoon;
+	smallint set_pgrp;
+};
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define sv        (G.sv        )
+#define svdir     (G.svdir     )
+#define rplog     (G.rplog     )
+#define svnum     (G.svnum     )
+#define rploglen  (G.rploglen  )
+#define logpipe   (G.logpipe   )
+#define pfd       (G.pfd       )
+#define stamplog  (G.stamplog  )
+#define check     (G.check     )
+#define exitsoon  (G.exitsoon  )
+#define set_pgrp  (G.set_pgrp  )
+#define INIT_G() do { \
+	check = 1; \
+} while (0)
 
 static void fatal2_cannot(const char *m1, const char *m2)
 {
@@ -222,6 +239,8 @@ int runsvdir_main(int argc ATTRIBUTE_UNUSED, char **argv)
 	char ch;
 	int i;
 
+	INIT_G();
+
 	argv++;
 	if (!*argv)
 		bb_show_usage();