patch 9.0.1901: win32: not correctly freeing environment

Problem:  win32: not correctly freeing environment
Solution: After we call GetEnvironmentStringsW, we should call
          FreeEnvironmentStringsW

closes: #13096
closes: #13094

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Ken Takata <kentkt@csc.jp>
diff --git a/src/os_win32.c b/src/os_win32.c
index ff60e04..7891944 100644
--- a/src/os_win32.c
+++ b/src/os_win32.c
@@ -5788,7 +5788,7 @@
 		*((WCHAR*)gap->ga_data + gap->ga_len++) = *p;
 	    p++;
 	}
-	FreeEnvironmentStrings(base);
+	FreeEnvironmentStringsW(base);
 	*((WCHAR*)gap->ga_data + gap->ga_len++) = L'\0';
     }