build: mark all PE files as wine builtins
This allows libmono to load extra libraries (notably win-iconv) from system_dllpath.
For example, Fedora's wine-mono is built against a shared win-iconv installed in system_dllpath, but wine will not search there unless it's explicitly instructed to do so since wine commit bfbccf1a (ntdll: Prevent loading Wine system dependencies in place of identically named application DLLs.).
wine/wine!7077 Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=54573