Fix libfido2 detection on OpenBSD

--- Telegram/cmake/lib_fido2.cmake.orig	Thu Aug  6 16:46:40 2026
+++ Telegram/cmake/lib_fido2.cmake	Fri Aug 14 21:44:56 2026
@@ -9,6 +9,13 @@
 # On Windows it serves only systems without webauthn.dll (Win7/8/8.1,
 # Win10 < 1903); winhello.c is left out.
 
+if (CMAKE_SYSTEM_NAME STREQUAL "OpenBSD")
+   add_library(lib_fido2 INTERFACE)
+   add_library(tdesktop::lib_fido2 ALIAS lib_fido2)
+   target_link_libraries(lib_fido2 INTERFACE fido2)
+   return()
+endif()
+
 if (DESKTOP_APP_USE_PACKAGED)
     find_package(PkgConfig)
     if (PkgConfig_FOUND)
