gdb: Replace gdb::optional with std::optional

Since GDB now requires C++17, we don't need the internally maintained
gdb::optional implementation.  This patch does the following replacing:
  - gdb::optional -> std::optional
  - gdb::in_place -> std::in_place
  - #include "gdbsupport/gdb_optional.h" -> #include <optional>

This change has mostly been done automatically.  One exception is
gdbsupport/thread-pool.* which did not use the gdb:: prefix as it
already lives in the gdb namespace.

Change-Id: I19a92fa03e89637bab136c72e34fd351524f65e9
Approved-By: Tom Tromey <tom@tromey.com>
Approved-By: Pedro Alves <pedro@palves.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/gdb/main.c b/gdb/main.c
index 2da39f8..486c1ff 100644
--- a/gdb/main.c
+++ b/gdb/main.c
@@ -361,7 +361,7 @@ get_init_files (std::vector<std::string> *system_gdbinit,
 {
   /* Cache the file lookup object so we only actually search for the files
      once.  */
-  static gdb::optional<gdb_initfile_finder> init_files;
+  static std::optional<gdb_initfile_finder> init_files;
   if (!init_files.has_value ())
     init_files.emplace (GDBINIT, SYSTEM_GDBINIT, SYSTEM_GDBINIT_RELOCATABLE,
 			SYSTEM_GDBINIT_DIR, SYSTEM_GDBINIT_DIR_RELOCATABLE,
@@ -381,7 +381,7 @@ get_earlyinit_files (std::string *home_gdbearlyinit)
 {
   /* Cache the file lookup object so we only actually search for the files
      once.  */
-  static gdb::optional<gdb_initfile_finder> init_files;
+  static std::optional<gdb_initfile_finder> init_files;
   if (!init_files.has_value ())
     init_files.emplace (GDBEARLYINIT, nullptr, false, nullptr, false, false);