From 7de6671dc2db10d3a3617442e1b218361f281ddf Mon Sep 17 00:00:00 2001
From: Martijn Otto <git@martijnotto.nl>
Date: Thu, 5 Sep 2019 17:27:12 +0200
Subject: [PATCH] Add the iwyu target to get information on unused headers

With this change, building the iwyu target will provide information
on unused headers, which can be removed to reduce compilation times.
---
 CMakeLists.txt | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 60fcf130e..4cc8d2296 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -27,6 +27,9 @@
 # THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #
 # Parts of this file are originally copyright (c) 2012-2013 The Cryptonote developers
+
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
 list(INSERT CMAKE_MODULE_PATH 0
   "${CMAKE_SOURCE_DIR}/cmake")
 include(CheckCCompilerFlag)
@@ -1048,3 +1051,13 @@ option(INSTALL_VENDORED_LIBUNBOUND "Install libunbound binary built from source
 
 
 CHECK_C_COMPILER_FLAG(-std=c11 HAVE_C11)
+
+find_package(PythonInterp)
+find_program(iwyu_tool_path NAMES iwyu_tool.py iwyu_tool)
+if (iwyu_tool_path AND PYTHONINTERP_FOUND)
+  add_custom_target(iwyu
+    COMMAND "${PYTHON_EXECUTABLE}" "${iwyu_tool_path}" -p "${CMAKE_BINARY_DIR}" -- --no_fwd_decls
+    COMMENT "Running include-what-you-use tool"
+    VERBATIM
+  )
+endif()