[Darwin] Fix two off-by-one errors in the driver.

2019-06-19  Iain Sandoe  <iain@sandoe.co.uk>

        * config/darwin-driver.c (darwin_driver_init): Fix off-by-one errors
        in computing the number of options to be moved.

From-SVN: r272479

gcc/ChangeLog

+2019-06-19  Iain Sandoe  <iain@sandoe.co.uk>
+
+        * config/darwin-driver.c (darwin_driver_init): Fix off-by-one errors
+        in computing the number of options to be moved.
+
 2019-06-19  Maya Rashish  <coypu@sdf.org>
 
 	*  config/arm/netbsd-elf.h (SYSARCH_ARM_SYNC_ICACHE): New definition.

gcc/config/darwin-driver.c

@@ -261,7 +261,7 @@ darwin_driver_init (unsigned int *decoded_options_count,
 	  if (*decoded_options_count > i) {
 	    memmove (*decoded_options + i,
 		     *decoded_options + i + 1,
-		     ((*decoded_options_count - i)
+		     ((*decoded_options_count - i - 1)
 		      * sizeof (struct cl_decoded_option)));
 	  }
 	  --i;
@@ -307,7 +307,7 @@ darwin_driver_init (unsigned int *decoded_options_count,
 	  if (*decoded_options_count > i) {
 	    memmove (*decoded_options + i,
 		     *decoded_options + i + 1,
-		     ((*decoded_options_count - i)
+		     ((*decoded_options_count - i - 1)
 		      * sizeof (struct cl_decoded_option)));
 	  }
 	  --i;