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

--- textdocument/lib/CMakeLists.txt.orig	2016-08-10 16:10:17 UTC
+++ textdocument/lib/CMakeLists.txt
@@ -58,7 +58,7 @@ install(TARGETS Grantlee_TextDocument EX
          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/grantlee5
 )

 install(FILES
