Add some const qualifiers

There was a mismatch between the const qualifiers for
excludeDirContents in src/backend/backup/basebackup.c and
src/bin/pg_rewind/filemap.c, which led to a quick search for similar
cases.  We should make excludeDirContents match, but the rest of the
changes seem like a good idea as well.

Author: David Steele <david@pgmasters.net>
Discussion: https://www.postgresql.org/message-id/flat/669a035c-d23d-2f38-7ff0-0cb93e01d610@pgmasters.net

contrib/fuzzystrmatch/fuzzystrmatch.c

@@ -55,7 +55,7 @@ static void _soundex(const char *instr, char *outstr);
 #define SOUNDEX_LEN 4
 
 /*									ABCDEFGHIJKLMNOPQRSTUVWXYZ */
-static const char *soundex_table = "01230120022455012623010202";
+static const char *const soundex_table = "01230120022455012623010202";
 
 static char
 soundex_code(char letter)

contrib/pgcrypto/pgp-armor.c

@@ -178,8 +178,8 @@ pg_base64_dec_len(unsigned srclen)
  * PGP armor
  */
 
-static const char *armor_header = "-----BEGIN PGP MESSAGE-----\n";
+static const char *const armor_header = "-----BEGIN PGP MESSAGE-----\n";
-static const char *armor_footer = "\n-----END PGP MESSAGE-----\n";
+static const char *const armor_footer = "\n-----END PGP MESSAGE-----\n";
 
 /* CRC24 implementation from rfc2440 */
 #define CRC24_INIT 0x00b704ceL

src/backend/catalog/heap.c

@@ -228,7 +228,7 @@ static const FormData_pg_attribute a6 = {
 	.attislocal = true,
 };
 
-static const FormData_pg_attribute *SysAtt[] = {&a1, &a2, &a3, &a4, &a5, &a6};
+static const FormData_pg_attribute *const SysAtt[] = {&a1, &a2, &a3, &a4, &a5, &a6};
 
 /*
  * This function returns a Form_pg_attribute pointer for a system attribute.

src/backend/utils/adt/ruleutils.c

@@ -316,9 +316,9 @@ typedef void (*rsv_callback) (Node *node, deparse_context *context,
  * ----------
  */
 static SPIPlanPtr plan_getrulebyoid = NULL;
-static const char *query_getrulebyoid = "SELECT * FROM pg_catalog.pg_rewrite WHERE oid = $1";
+static const char *const query_getrulebyoid = "SELECT * FROM pg_catalog.pg_rewrite WHERE oid = $1";
 static SPIPlanPtr plan_getviewrule = NULL;
-static const char *query_getviewrule = "SELECT * FROM pg_catalog.pg_rewrite WHERE ev_class = $1 AND rulename = $2";
+static const char *const query_getviewrule = "SELECT * FROM pg_catalog.pg_rewrite WHERE ev_class = $1 AND rulename = $2";
 
 /* GUC parameters */
 bool		quote_all_identifiers = false;

src/backend/utils/misc/guc.c

@@ -112,7 +112,7 @@ typedef struct
 #error XLOG_BLCKSZ must be between 1KB and 1MB
 #endif
 
-static const char *memory_units_hint = gettext_noop("Valid units for this parameter are \"B\", \"kB\", \"MB\", \"GB\", and \"TB\".");
+static const char *const memory_units_hint = gettext_noop("Valid units for this parameter are \"B\", \"kB\", \"MB\", \"GB\", and \"TB\".");
 
 static const unit_conversion memory_unit_conversion_table[] =
 {
@@ -149,7 +149,7 @@ static const unit_conversion memory_unit_conversion_table[] =
 	{""}						/* end of table marker */
 };
 
-static const char *time_units_hint = gettext_noop("Valid units for this parameter are \"us\", \"ms\", \"s\", \"min\", \"h\", and \"d\".");
+static const char *const time_units_hint = gettext_noop("Valid units for this parameter are \"us\", \"ms\", \"s\", \"min\", \"h\", and \"d\".");
 
 static const unit_conversion time_unit_conversion_table[] =
 {

src/bin/initdb/initdb.c

@@ -218,8 +218,8 @@ static bool authwarning = false;
  * but here it is more convenient to pass it as an environment variable
  * (no quoting to worry about).
  */
-static const char *boot_options = "-F -c log_checkpoints=false";
+static const char *const boot_options = "-F -c log_checkpoints=false";
-static const char *backend_options = "--single -F -O -j -c search_path=pg_catalog -c exit_on_error=true -c log_checkpoints=false";
+static const char *const backend_options = "--single -F -O -j -c search_path=pg_catalog -c exit_on_error=true -c log_checkpoints=false";
 
 /* Additional switches to pass to backend (either boot or standalone) */
 static char *extra_options = "";

src/bin/pg_amcheck/pg_amcheck.c

@@ -166,7 +166,7 @@ typedef struct RelationInfo
  * Query for determining if contrib's amcheck is installed.  If so, selects the
  * namespace name where amcheck's functions can be found.
  */
-static const char *amcheck_sql =
+static const char *const amcheck_sql =
 "SELECT n.nspname, x.extversion FROM pg_catalog.pg_extension x"
 "\nJOIN pg_catalog.pg_namespace n ON x.extnamespace = n.oid"
 "\nWHERE x.extname = 'amcheck'";

src/bin/pg_rewind/filemap.c

@@ -85,7 +85,7 @@ struct exclude_list_item
  * they are defined in backend-only headers.  So this list is maintained
  * with a best effort in mind.
  */
-static const char *excludeDirContents[] =
+static const char *const excludeDirContents[] =
 {
 	/*
 	 * Skip temporary statistics files. PG_STAT_TMP_DIR must be skipped

src/bin/pg_rewind/parsexlog.c

@@ -31,7 +31,7 @@
 #define PG_RMGR(symname,name,redo,desc,identify,startup,cleanup,mask,decode) \
   name,
 
-static const char *RmgrNames[RM_MAX_ID + 1] = {
+static const char *const RmgrNames[RM_MAX_ID + 1] = {
 #include "access/rmgrlist.h"
 };
 

src/bin/pgbench/pgbench.c

@@ -231,7 +231,7 @@ typedef enum
 } partition_method_t;
 
 static partition_method_t partition_method = PART_NONE;
-static const char *PARTITION_METHOD[] = {"none", "range", "hash"};
+static const char *const PARTITION_METHOD[] = {"none", "range", "hash"};
 
 /* random seed used to initialize base_random_sequence */
 int64		random_seed = -1;
@@ -709,7 +709,7 @@ typedef enum QueryMode
 } QueryMode;
 
 static QueryMode querymode = QUERY_SIMPLE;
-static const char *QUERYMODE[] = {"simple", "extended", "prepared"};
+static const char *const QUERYMODE[] = {"simple", "extended", "prepared"};
 
 /*
  * struct Command represents one command in a script.

src/interfaces/libpq/pqexpbuffer.c

@@ -38,7 +38,7 @@
 static const char oom_buffer[1] = "";
 
 /* Need a char * for unconstify() compatibility */
-static const char *oom_buffer_ptr = oom_buffer;
+static const char *const oom_buffer_ptr = oom_buffer;
 
 
 /*