[libcxx] [test] Use _putenv instead of setenv on windows

[ldionne]

libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.temp_dir_path/temp_directory_path.pass.cpp

30

Can we move this to filesystem_test_helper.h?

[mstorsjo]

Moved to the helper header, so this then goes on top of D89530.

libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.temp_dir_path/temp_directory_path.pass.cpp

 
 #include "test_macros.h"
 #include "rapid-cxx-test.h"
 #include "filesystem_test_helper.h"
 
 using namespace fs;
 
 void PutEnv(std::string var, fs::path value) {
-    assert(::setenv(var.c_str(), value.string().c_str(), /* overwrite */ 1) == 0);
+    assert(utils::setenv(var.c_str(), value.string().c_str(), /* overwrite */ 1) == 0);
 }
 
 void UnsetEnv(std::string var) {
-    assert(::unsetenv(var.c_str()) == 0);
+    assert(utils::unsetenv(var.c_str()) == 0);
 }
 
 TEST_SUITE(filesystem_temp_directory_path_test_suite)
 
 TEST_CASE(signature_test)
 {
     std::error_code ec; ((void)ec);
     ASSERT_NOT_NOEXCEPT(temp_directory_path());

libcxx/test/support/filesystem_test_helper.h

inline int symlink(const char* oldname, const char* newname, bool is_dir) {
           return 0;
         if (GetLastError() != ERROR_INVALID_PARAMETER)
           return 1;
         return !CreateSymbolicLinkA(newname, oldname, flags);
     }
     inline int link(const char *oldname, const char* newname) {
         return !CreateHardLinkA(newname, oldname, NULL);
     }
+    inline int setenv(const char *var, const char *val, int overwrite) {
+        (void)overwrite;
+        return ::_putenv((std::string(var) + "=" + std::string(val)).c_str());
+    }
+    inline int unsetenv(const char *var) {
+        return ::_putenv((std::string(var) + "=").c_str());
+    }
 #else
     using ::mkdir;
     using ::ftruncate;
     inline int symlink(const char* oldname, const char* newname, bool is_dir) { (void)is_dir; return ::symlink(oldname, newname); }
     using ::link;
+    inline int setenv(const char *var, const char *val, int overwrite) {
+        return ::setenv(var, val, overwrite);
+    }
+    inline int unsetenv(const char *var) {
+        return ::unsetenv(var);
+    }
 #endif
 
     inline std::string getcwd() {
         // Assume that path lengths are not greater than this.
         // This should be fine for testing purposes.
         char buf[4096];
         char* ret = ::getcwd(buf, sizeof(buf));
         assert(ret && "getcwd failed");