Copy all files with given extension to output directory using CMake

I've found the solution by myself:

file(GLOB MY_PUBLIC_HEADERS
  "myDir/*.h"
)
file(COPY ${MY_PUBLIC_HEADERS} DESTINATION myDestination)

this also works for me:

install(DIRECTORY "myDir/" 
        DESTINATION "myDestination" 
        FILES_MATCHING PATTERN "*.h" )