+#if HAVE_DECL__PUTENV
+ /* Rely on _putenv to allocate the new environment. If other
+ parts of the application use _putenv, the !HAVE_DECL__PUTENV code
+ would fight over who owns the environ vector, causing a crash. */
+ if (name_end[1])
+ return _putenv (string);
+ else
+ {
+ /* _putenv ("NAME=") unsets NAME, so invoke _putenv ("NAME= ")
+ to allocate the environ vector and then replace the new
+ entry with "NAME=". */
+ int putenv_result, putenv_errno;
+ char *name_x = malloc (name_end - string + sizeof "= ");
+ if (!name_x)
+ return -1;
+ memcpy (name_x, string, name_end - string + 1);
+ name_x[name_end - string + 1] = ' ';
+ name_x[name_end - string + 2] = 0;
+ putenv_result = _putenv (name_x);
+ putenv_errno = errno;
+ for (ep = environ; *ep; ep++)
+ if (strcmp (*ep, name_x) == 0)
+ {
+ *ep = string;
+ break;
+ }
+# if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+ if (putenv_result == 0)
+ {
+ /* _putenv propagated "NAME= " into the subprocess environment;
+ fix that by calling SetEnvironmentVariable directly. */
+ name_x[name_end - string] = 0;
+ putenv_result = SetEnvironmentVariable (name_x, "") ? 0 : -1;
+ putenv_errno = ENOMEM; /* ENOMEM is the only way to fail. */
+ }
+# endif
+ free (name_x);
+ __set_errno (putenv_errno);
+ return putenv_result;
+ }
+#else
+ for (ep = environ; *ep; ep++)
+ if (strncmp (*ep, string, name_end - string) == 0
+ && (*ep)[name_end - string] == '=')