Bug#45288: pb2 returns a lot of compilation warnings on linux

Fix warnings flagged by the new warning option -Wunused-but-set-variable
that was added to GCC 4.6 and that is enabled by -Wunused and -Wall. The
option causes a warning whenever a local variable is assigned to but is
later unused. It also warns about meaningless pointer dereferences.

client/mysql.cc:
  Meaningless pointer dereferences.
client/mysql_upgrade.c:
  Check whether reading from the file succeeded.
extra/comp_err.c:
  Unused.
extra/yassl/src/yassl_imp.cpp:
  Skip instead of reading data that is discarded.
include/my_pthread.h:
  Variable is only used in debug builds.
include/mysys_err.h:
  Add new error messages.
mysys/errors.c:
  Add new error message for permission related functions.
mysys/mf_iocache.c:
  Variable is only checked under THREAD.
mysys/my_copy.c:
  Raise a error if chmod or chown fails.
mysys/my_redel.c:
  Raise a error if chmod or chown fails.
regex/engine.c:
  Use a equivalent variable for the assert.
server-tools/instance-manager/instance_options.cc:
  Unused.
sql/field.cc:
  Unused.
sql/item.cc:
  Unused.
sql/log.cc:
  Do not ignore the return value of freopen: only set buffer if
  reopening succeeds.
  
  Adjust doxygen comment to the right function.
  
  Pass message lenght to log function.
sql/mysqld.cc:
  Do not ignore the return value of freopen: only set buffer if
  reopening succeeds.
sql/partition_info.cc:
  Unused.
sql/slave.cc:
  No need to set pointer to the address of '\0'.
sql/spatial.cc:
  Unused. Left for historical purposes.
sql/sql_acl.cc:
  Unused.
sql/sql_base.cc:
  Pointers are always set to the same variables.
sql/sql_parse.cc:
  End statement if reading fails.
  
  Store the buffer after it has actually been updated.
sql/sql_repl.cc:
  No need to set pointer to the address of '\0'.
sql/sql_show.cc:
  Put variable under the same ifdef block.
sql/udf_example.c:
  Set null pointer flag appropriately.
storage/csv/ha_tina.cc:
  Meaningless dereferences.
storage/example/ha_example.cc:
  Return the error since it's available.
storage/myisam/mi_locking.c:
  Remove unused and dead code.

1 files changed, 7 insertions, 10 deletions

diff --git a/regex/engine.c b/regex/engine.c
index 1968ca61a96..be08adf8601 100644
--- a/regex/engine.c
+++ b/regex/engine.c
@@ -256,7 +256,6 @@ sopno stopst;
 	register char *ssp;	/* start of string matched by subsubRE */
 	register char *sep;	/* end of string matched by subsubRE */
 	register char *oldssp;	/* previous ssp */
-	register char *dp;      /* used in debug mode to check asserts */
 
 	AT("diss", start, stop, startst, stopst);
 	sp = start;
@@ -314,11 +313,9 @@ sopno stopst;
 			ssub = ss + 1;
 			esub = es - 1;
 			/* did innards match? */
-			if (slow(charset, m, sp, rest, ssub, esub) != NULL) {
-				dp = dissect(charset, m, sp, rest, ssub, esub);
-				assert(dp == rest);
-			} else		/* no */
-				assert(sp == rest);
+			if (slow(charset, m, sp, rest, ssub, esub) != NULL)
+				sp = dissect(charset, m, sp, rest, ssub, esub);
+			assert(sp == rest);
 			sp = rest;
 			break;
 		case OPLUS_:
@@ -353,8 +350,8 @@ sopno stopst;
 			}
 			assert(sep == rest);	/* must exhaust substring */
 			assert(slow(charset, m, ssp, sep, ssub, esub) == rest);
-			dp = dissect(charset, m, ssp, sep, ssub, esub);
-			assert(dp == sep);
+			sp = dissect(charset, m, ssp, sep, ssub, esub);
+			assert(sp == sep);
 			sp = rest;
 			break;
 		case OCH_:
@@ -388,8 +385,8 @@ sopno stopst;
 				else
 					assert(OP(m->g->strip[esub]) == O_CH);
 			}
-			dp = dissect(charset, m, sp, rest, ssub, esub);
-			assert(dp == rest);
+			sp = dissect(charset, m, sp, rest, ssub, esub);
+			assert(sp == rest);
 			sp = rest;
 			break;
 		case O_PLUS: