chan_unistim: fix char type to have consistent behavior on ARM

There is difference exists in behaviour of char type on x86 and ARM.
On x86 by default char variable type means signed char, but in ARM
unsigned char used. This make binary calculations and negative values
works wrong on ARM.

This patch change type of char variables used for store negative
values and binary calculations to signed char.

ASTERISK-26714

Change-Id: Id78716dee9568a58419d4ef63c038affc3dfc7ab

channels/chan_unistim.c

@@ -161,6 +161,7 @@ enum autoprov_extn {
 #define LED_HEADPHONE_ON		0x011
 #define LED_MUTE_OFF			0x018
 #define LED_MUTE_ON			0x019
+#define LED_MUTE_BLINK			0x1A
 
 #define SIZE_HEADER	     6
 #define SIZE_MAC_ADDR	   17
@@ -357,8 +358,8 @@ struct unistim_subchannel {
 	int softkey;			/*! Softkey assigned */
 	pthread_t ss_thread;		/*! unistim_ss thread handle */
 	int alreadygone;
-	char ringvolume;
-	char ringstyle;
+	signed char ringvolume;
+	signed char ringstyle;
 	int moh;					/*!< Music on hold in progress */
 	AST_LIST_ENTRY(unistim_subchannel) list;
 };
@@ -413,13 +414,13 @@ static struct unistim_device {
 	char maintext2[25];		     /*!< when the phone is idle, display this string on line 2 */
 	char titledefault[13];	  /*!< title (text before date/time) */
 	char datetimeformat;	    /*!< format used for displaying time/date */
-	char contrast;			  /*!< contrast */
+	signed char contrast;			  /*!< contrast */
 	char country[3];			/*!< country used for dial tone frequency */
 	struct ast_tone_zone *tz;	       /*!< Tone zone for res_indications (ring, busy, congestion) */
-	char ringvolume;			/*!< Ring volume */
-	char ringstyle;			 /*!< Ring melody */
-	char cwvolume;			/*!< Ring volume on call waiting */
-	char cwstyle;			 /*!< Ring melody on call waiting */
+	signed char ringvolume;			/*!< Ring volume */
+	signed char ringstyle;			 /*!< Ring melody */
+	signed char cwvolume;			/*!< Ring volume on call waiting */
+	signed char cwstyle;			 /*!< Ring melody on call waiting */
 	int interdigit_timer;		/*!< Interdigit timer for dialing number by timeout */
 	int dtmfduration;		/*!< DTMF playback duration */
 	time_t nextdial;		/*!< Timer used for dial by timeout */
@@ -443,7 +444,7 @@ static struct unistim_device {
 	int nat;					/*!< Used by the obscure ast_rtp_setnat */
 	enum autoprov_extn extension;   /*!< See ifdef EXTENSION for valid values */
 	char extension_number[11];      /*!< Extension number entered by the user */
-	char to_delete;			 /*!< Used in reload */
+	signed char to_delete;			 /*!< Used in reload */
 	struct ast_silence_generator *silence_generator;
 	AST_LIST_HEAD(,unistim_subchannel) subs; /*!< pointer to our current connection, channel... */
 	AST_LIST_HEAD(,unistim_line) lines;
@@ -1701,7 +1702,7 @@ send_select_output(struct unistimsession *pte, unsigned char output, unsigned ch
 	}
 	pte->device->output = output;
 }
-static void send_ring(struct unistimsession *pte, char volume, char style)
+static void send_ring(struct unistimsession *pte, signed char volume, signed char style)
 {
 	BUFFSEND;
 	if (unistimdebug) {
@@ -4835,7 +4836,7 @@ static int unistim_call(struct ast_channel *ast, const char *dest, int timeout)
 	int res = 0, i;
 	struct unistim_subchannel *sub, *sub_real;
 	struct unistimsession *session;
-	char ringstyle, ringvolume;
+	signed char ringstyle, ringvolume;
 
 	session = channel_to_session(ast);
 	if (!session) {
@@ -5438,8 +5439,8 @@ static struct unistim_subchannel *find_subchannel_by_name(const char *dest)
 							if ((*at < '0') || (*at > '7')) { /* ring style */
 								ast_log(LOG_WARNING, "Invalid ring selection (%s)", at);
 							} else {
-								char ring_volume = -1;
-								char ring_style = *at - '0';
+								signed char ring_volume = -1;
+								signed char ring_style = *at - '0';
 								at++;
 								if ((*at >= '0') && (*at <= '3')) {      /* ring volume */
 									ring_volume = *at - '0';
@@ -6483,7 +6484,7 @@ static struct unistim_device *build_device(const char *cat, const struct ast_var
 	int create = 1;
 	int nbsoftkey, dateformat, timeformat, callhistory, sharpdial, linecnt;
 	char linelabel[AST_MAX_EXTENSION];
-	char ringvolume, ringstyle, cwvolume, cwstyle;
+	signed char ringvolume, ringstyle, cwvolume, cwstyle;
 
 	/* First, we need to know if we already have this name in our list */
 	/* Get a lock for the device chained list */