find_package(PkgConfig)
if (PKG_CONFIG_FOUND)
    if (GTK3_FIND_REQUIRED)
        set(_pkgconfig_REQUIRED REQUIRED)
    endif ()
    pkg_check_modules(GTK3 ${_pkgconfig_REQUIRED} gtk+-3.0)
else ()
    find_path(GTK3_INCLUDE_DIRS gtk.h)
    # find_library(GTK3_LIBRARIES)
    if (GTK3_INCLUDE_DIRS AND GTK3_LIBRARIES)
        set(GTK3_FOUND 1)
        if (NOT GTK3_FIND_QUIETLY)
            message(STATUS "Found GTK3: ${GTK3_LIBRARIES}")
        endif ()
    elseif (GTK3_FIND_REQUIRED)
        message(SEND_ERROR "Could not find GTK3")
    elseif (NOT GTK3_FIND_QUIETLY)
        message(STATUS "Could not find GTK3")
    endif ()
endif ()
mark_as_advanced(GTK3_INCLUDE_DIRS GTK3_LIBRARIES)