Mark misc static global variables as const

Reviewed-by: Andres Freund
Discussion: https://www.postgresql.org/message-id/54c29fb0-edf2-48ea-9814-44e918bbd6e8@iki.fi

contrib/btree_gist/btree_interval.c

@@ -113,7 +113,7 @@ static const gbtree_ninfo tinfo =
 Interval *
 abs_interval(Interval *a)
 {
-	static Interval zero = {0, 0, 0};
+	static const Interval zero = {0, 0, 0};
 
 	if (DatumGetBool(DirectFunctionCall2(interval_lt,
 										 IntervalPGetDatum(a),

contrib/oid2name/oid2name.c

@@ -62,7 +62,7 @@ void		sql_exec_dumpalltbspc(PGconn *conn, struct options *opts);
 void
 get_opts(int argc, char **argv, struct options *my_opts)
 {
-	static struct option long_options[] = {
+	static const struct option long_options[] = {
 		{"dbname", required_argument, NULL, 'd'},
 		{"host", required_argument, NULL, 'h'},
 		{"host", required_argument, NULL, 'H'}, /* deprecated */

src/backend/access/transam/xlogprefetcher.c

@@ -362,7 +362,7 @@ XLogPrefetcher *
 XLogPrefetcherAllocate(XLogReaderState *reader)
 {
 	XLogPrefetcher *prefetcher;
-	static HASHCTL hash_table_ctl = {
+	const HASHCTL hash_table_ctl = {
 		.keysize = sizeof(RelFileLocator),
 		.entrysize = sizeof(XLogPrefetcherFilter)
 	};

src/common/sha1.c

@@ -61,7 +61,7 @@
 #include "sha1_int.h"
 
 /* constant table */
-static uint32 _K[] = {0x5a827999, 0x6ed9eba1, 0x8f1bbcdc, 0xca62c1d6};
+static const uint32 _K[] = {0x5a827999, 0x6ed9eba1, 0x8f1bbcdc, 0xca62c1d6};
 
 #define K(t)	_K[(t) / 20]
 

src/pl/plpython/plpy_cursorobject.c

@@ -27,7 +27,7 @@ static PyObject *PLy_cursor_iternext(PyObject *self);
 static PyObject *PLy_cursor_fetch(PyObject *self, PyObject *args);
 static PyObject *PLy_cursor_close(PyObject *self, PyObject *unused);
 
-static char PLy_cursor_doc[] = "Wrapper around a PostgreSQL cursor";
+static const char PLy_cursor_doc[] = "Wrapper around a PostgreSQL cursor";
 
 static PyMethodDef PLy_cursor_methods[] = {
 	{"fetch", PLy_cursor_fetch, METH_VARARGS, NULL},