libstdc++: Use secure_getenv for filesystem::temp_directory_path() [PR65018]

This adds a configure check for the GNU extension secure_getenv and then
uses it for looking up TMPDIR and similar variables.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	PR libstdc++/65018
	* configure.ac: Check for secure_getenv.
	* config.h.in: Regenerate.
	* configure: Regenerate.
	* src/filesystem/ops-common.h (get_temp_directory_from_env): New
	helper function to obtain path from the environment.
	* src/c++17/fs_ops.cc (fs::temp_directory_path): Use new helper.
	* src/filesystem/ops.cc (fs::temp_directory_path): Likewise.
	* testsuite/27_io/filesystem/operations/temp_directory_path.cc:
	Print messages if test cannot be run.
	* testsuite/experimental/filesystem/operations/temp_directory_path.cc:
	Likewise. Fix incorrect condition. Use "TMP" to work with
	Windows as well as POSIX.

1 files changed, 8 insertions, 1 deletions

diff --git a/libstdc++-v3/testsuite/experimental/filesystem/operations/temp_directory_path.cc b/libstdc++-v3/testsuite/experimental/filesystem/operations/temp_directory_path.cc
index 3e0833f..d6d251e 100644
--- a/libstdc++-v3/testsuite/experimental/filesystem/operations/temp_directory_path.cc
+++ b/libstdc++-v3/testsuite/experimental/filesystem/operations/temp_directory_path.cc
@@ -21,6 +21,7 @@
 
 #include <experimental/filesystem>
 #include <stdlib.h>
+#include <stdio.h>
 #include <testsuite_hooks.h>
 #include <testsuite_fs.h>
 
@@ -59,7 +60,10 @@ test01()
   clean_env();
 
   if (!fs::exists("/tmp"))
+  {
+    puts("/tmp doesn't exist, not testing it for temp_directory_path");
     return; // just give up
+  }
 
   std::error_code ec = make_error_code(std::errc::invalid_argument);
   fs::path p1 = fs::temp_directory_path(ec);
@@ -75,8 +79,11 @@ test02()
 {
   clean_env();
 
-  if (set_env("TMPDIR", __gnu_test::nonexistent_path().string()))
+  if (!set_env("TMP", __gnu_test::nonexistent_path().string()))
+  {
+    puts("Cannot set environment variables, not testing temp_directory_path");
     return; // just give up
+  }
 
   std::error_code ec;
   fs::path p = fs::temp_directory_path(ec);