In pg_upgrade, rename macro EXEC_EXT to SHELL_EXT for clarity.

Backpatch to 9.0.X.

contrib/pg_upgrade/check.c

@@ -389,7 +389,7 @@ create_script_for_old_cluster_deletion(migratorContext *ctx,
 	prep_status(ctx, "Creating script to delete old cluster");
 
 	snprintf(*deletion_script_file_name, MAXPGPATH, "%s/delete_old_cluster.%s",
-			 ctx->cwd, EXEC_EXT);
+			 ctx->cwd, SHELL_EXT);
 
 	if ((script = fopen(*deletion_script_file_name, "w")) == NULL)
 		pg_log(ctx, PG_FATAL, "Could not create necessary file:  %s\n",

contrib/pg_upgrade/pg_upgrade.h

@@ -39,14 +39,14 @@
 #define pg_mv_file			rename
 #define pg_link_file		link
 #define RMDIR_CMD			"rm -rf"
-#define EXEC_EXT			"sh"
+#define SHELL_EXT			"sh"
 #else
 #define pg_copy_file		CopyFile
 #define pg_mv_file			pgrename
 #define pg_link_file		win32_pghardlink
 #define sleep(x)			Sleep(x * 1000)
 #define RMDIR_CMD			"RMDIR /s/q"
-#define EXEC_EXT			"bat"
+#define SHELL_EXT			"bat"
 #define EXE_EXT				".exe"
 #endif