[libcxx] [test] Fix get_temp_file_name() to compile for Windows.

[STL_MSFT]

Summary

[libcxx] [test] Fix get_temp_file_name() to compile for Windows.

It was including <io.h> but attempting to use GetTempPath() and GetTempFileName(), which are provided by <windows.h>.

Instead of dragging in <windows.h> (which is large), we can use _mktemp_s() from <io.h>.

Fixes MSVC errors:
"error C2065: 'MAX_PATH': undeclared identifier"
"error C3861: 'GetTempPath': identifier not found"
"error C3861: 'GetTempFileName': identifier not found"

[EricWF]

LGTM but I don't know much about Windows or MinGW.

[EricWF]

r267963.

[majnemer]

Er, I don't think mingw provides _mktemp_s.

[EricWF]

In D19702#416314, @majnemer wrote:

Er, I don't think mingw provides _mktemp_s.

I went back to the old method for MinGW in r267968 just to be safe. Thanks for the input.

[STL_MSFT]

[David Majnemer]

Er, I don't think mingw provides _mktemp_s.

Yeah, I don't know what needs to be done for MinGW. (I avoided using _mktemp for MSVC because I knew it would complain about "security".)

I am pretty sure that this code was already broken for MinGW - I grepped and found no inclusions of windows.h throughout the tests, and I believe that MinGW's io.h and other CRT headers don't declare the windows.h GetTempPath/etc. machinery that this was trying to use.

[Eric Fiselier]

I went back to the old method for MinGW in r267968 just to be safe. Thanks for the input.

I should have done that in the first place to be non-intrusive. Sorry for the minor headache.

STL

test/support/platform_support.h

 #define LOCALE_ru_RU_UTF_8     "ru_RU.UTF-8"
 #define LOCALE_zh_CN_UTF_8     "zh_CN.UTF-8"
 #endif
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string>
 #if defined(_WIN32) || defined(__MINGW32__)
-#include <io.h> // _mktemp
+#include <io.h> // _mktemp_s
 #else
 #include <unistd.h> // close
 #endif
 
 #if defined(_NEWLIB_VERSION) && defined(__STRICT_ANSI__)
 // Newlib provies this, but in the header it's under __STRICT_ANSI__
 extern "C" {
   int mkstemp(char*);
 }
 #endif
 
 #ifndef __CloudABI__
 inline
 std::string
 get_temp_file_name()
 {
 #if defined(_WIN32) || defined(__MINGW32__)
-    char Path[MAX_PATH+1];
-    char FN[MAX_PATH+1];
-    do { } while (0 == GetTempPath(MAX_PATH+1, Path));
-    do { } while (0 == GetTempFileName(Path, "libcxx", 0, FN));
-    return FN;
+    char Name[] = "libcxx.XXXXXX";
+
+    if (_mktemp_s(Name, sizeof(Name)) != 0) {
+        abort();
+    }
+
+    return Name;
 #else
     std::string Name;
     int FD = -1;
     do {
         Name = "libcxx.XXXXXX";
         FD = mkstemp(&Name[0]);
         if (FD == -1 && errno == EINVAL) {
             perror("mkstemp");