$NetBSD$

--- CMakeLists.txt.orig	2020-06-30 08:11:11.000000000 +0000
+++ CMakeLists.txt
@@ -206,7 +206,12 @@ if(EXISTS "${DEPRECATED_CONFIG_FILE}")
     message(FATAL_ERROR "${DEPRECATED_CONFIG_FILE} exists in the source directory, and will take precedence over the generated configuration in the build directory. Please remove this file before continuing. Alternatively, you can also clean your realm-core to remove this and other stale files: git clean -xfd")
 endif()
 
-set(PEGTL_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/src/external/pegtl/include/tao/)
+if(NOT PEGTL_SYSTEM)
+    set(PEGTL_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/src/external/pegtl/include/tao/)
+else()
+    find_path(PEGTL_INCLUDE_ROOTDIR tao/pegtl.hpp)
+    set(PEGTL_INCLUDE_DIR ${PEGTL_INCLUDE_ROOTDIR}/tao)
+endif()
 
 # Tell the build system where to find the sources (and generated sources)
 include_directories(src)
@@ -249,4 +254,3 @@ set(CPACK_ARCHIVE_COMPONENT_INSTALL ON)
 include(CPack)
 cpack_add_component(runtime DEPENDS runtime)
 cpack_add_component(devel DEPENDS devel)
-