grep: add -R

This adds -R option to grep similar to GNU grep. It is the same as -r
but also dereferences symbolic links to directories.

function                                             old     new   delta
grep_main                                            834     850     +16
packed_usage                                       33362   33368      +6
grep_file                                           1440    1441      +1
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/0 up/down: 23/0)               Total: 23 bytes

Signed-off-by: Tomi Leppanen <tomi.leppanen@jolla.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/findutils/grep.c b/findutils/grep.c
index 2cbe7ea..5b8644c 100644
--- a/findutils/grep.c
+++ b/findutils/grep.c
@@ -60,7 +60,7 @@
 
 /* options */
 //usage:#define grep_trivial_usage
-//usage:       "[-HhnlLoqvsriwFE"
+//usage:       "[-HhnlLoqvsrRiwFE"
 //usage:	IF_EXTRA_COMPAT("z")
 //usage:       "] [-m N] "
 //usage:	IF_FEATURE_GREP_CONTEXT("[-A/B/C N] ")
@@ -78,6 +78,7 @@
 //usage:     "\n	-v	Select non-matching lines"
 //usage:     "\n	-s	Suppress open and read errors"
 //usage:     "\n	-r	Recurse"
+//usage:     "\n	-R	Recurse and dereference symlinks"
 //usage:     "\n	-i	Ignore case"
 //usage:     "\n	-w	Match whole words only"
 //usage:     "\n	-x	Match whole lines only"
@@ -108,7 +109,7 @@
 
 /* -e,-f are lists; -m,-A,-B,-C have numeric param */
 #define OPTSTR_GREP \
-	"lnqvscFiHhe:*f:*Lorm:+wx" \
+	"lnqvscFiHhe:*f:*LorRm:+wx" \
 	IF_FEATURE_GREP_CONTEXT("A:+B:+C:+") \
 	"E" \
 	IF_EXTRA_COMPAT("z") \
@@ -131,6 +132,7 @@
 	OPTBIT_L, /* list unmatched file names only */
 	OPTBIT_o, /* show only matching parts of lines */
 	OPTBIT_r, /* recurse dirs */
+	OPTBIT_R, /* recurse dirs and symlinks to dirs */
 	OPTBIT_m, /* -m MAX_MATCHES */
 	OPTBIT_w, /* -w whole word match */
 	OPTBIT_x, /* -x whole line match */
@@ -154,6 +156,7 @@
 	OPT_L = 1 << OPTBIT_L,
 	OPT_o = 1 << OPTBIT_o,
 	OPT_r = 1 << OPTBIT_r,
+	OPT_R = 1 << OPTBIT_R,
 	OPT_m = 1 << OPTBIT_m,
 	OPT_w = 1 << OPTBIT_w,
 	OPT_x = 1 << OPTBIT_x,
@@ -687,6 +690,7 @@
 	int matched = 0;
 	recursive_action(dir,
 		/* recurse=yes */ ACTION_RECURSE |
+		/* followLinks=always */ ((option_mask32 & OPT_R) ? ACTION_FOLLOWLINKS : 0) |
 		/* followLinks=command line only */ ACTION_FOLLOWLINKS_L0 |
 		/* depthFirst=yes */ ACTION_DEPTHFIRST,
 		/* fileAction= */ file_action_grep,
@@ -827,7 +831,7 @@
 		if (!cur_file || LONE_DASH(cur_file)) {
 			cur_file = "(standard input)";
 		} else {
-			if (option_mask32 & OPT_r) {
+			if (option_mask32 & (OPT_r|OPT_R)) {
 				struct stat st;
 				if (stat(cur_file, &st) == 0 && S_ISDIR(st.st_mode)) {
 					if (!(option_mask32 & OPT_h))