- cmake: restore pthread/libm in libde265.pc Libs.private
  c8a3d1b52ec7322495cee9887d93dcd7e5fc7270

Index: libde265/CMakeLists.txt
--- libde265/CMakeLists.txt.orig
+++ libde265/CMakeLists.txt
@@ -106,6 +106,10 @@ endif()
 
 add_library(de265 ${libde265_sources} ${libde265_public_headers} ${ENCODER_OBJECTS} ${X86_OBJECTS} ${ARM_OBJECTS})
 target_include_directories(de265 PRIVATE ${CMAKE_BINARY_DIR} ${CMAKE_CURRENT_BINARY_DIR})
+target_link_libraries(de265 PRIVATE Threads::Threads)
+if(UNIX)
+  target_link_libraries(de265 PRIVATE m)
+endif()
 
 write_basic_package_version_file(libde265-config-version.cmake COMPATIBILITY ExactVersion)
 
