+function(pkgconfig_export VAR VAL)
+ get_property(PREV GLOBAL PROPERTY PKGCONFIG_${VAR})
+ set_property(GLOBAL PROPERTY PKGCONFIG_${VAR} "${PREV} ${VAL}")
+endfunction()
+macro(pkgconfig_import VAR)
+ get_property(PKGCONFIG_${VAR} GLOBAL PROPERTY PKGCONFIG_${VAR})
+endmacro()
+