Install headers prefixed, as to not cause a possible conflict with
different versions.

--- textdocument/lib/CMakeLists.txt.orig	2016-08-10 16:06:47 UTC
+++ textdocument/lib/CMakeLists.txt
@@ -44,7 +44,7 @@ install(TARGETS grantlee_gui EXPORT gran
          RUNTIME DESTINATION ${BIN_INSTALL_DIR} COMPONENT TextDocument
          LIBRARY DESTINATION ${LIB_INSTALL_DIR} COMPONENT TextDocument
          ARCHIVE DESTINATION ${LIB_INSTALL_DIR} COMPONENT TextDocument
-         INCLUDES DESTINATION include
+         INCLUDES DESTINATION include/grantlee4
 )

 install(FILES