From c9addec232f55fcaa03f1596b1eabb1427bd33c0 Mon Sep 17 00:00:00 2001
From: Thomas Devoogdt <thomas@devoogdt.com>
Date: Fri, 28 Apr 2023 10:25:16 +0200
Subject: [PATCH] build: use the system provided LuaJIT if found

e.g. buildroot has logic to build luajit,
so if pkg_check_modules can find a suitable version,
then use that one if -DFLB_PREFER_SYSTEM_LIB_LUAJIT=Yes.

Signed-off-by: Thomas Devoogdt <thomas@devoogdt.com>
---
 CMakeLists.txt      | 15 ++++++++++++++-
 cmake/headers.cmake |  4 ----
 cmake/luajit.cmake  |  5 +++++
 src/CMakeLists.txt  |  2 +-
 4 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0e2a880b277..b894968f109 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -176,6 +176,10 @@ option(FLB_HTTP_CLIENT_DEBUG  "Enable HTTP Client debug callbacks"   No)
 # Run ldconfig on package post-install
 option(FLB_RUN_LDCONFIG "Enable execution of ldconfig after installation" No)
 
+# Prefer system libraries if available
+option(FLB_PREFER_SYSTEM_LIBS             "Prefer system libraries"                   No)
+option(FLB_PREFER_SYSTEM_LIB_LUAJIT       "Prefer the libluajit system library"       ${FLB_PREFER_SYSTEM_LIBS})
+
 # Enable all features
 if(FLB_ALL)
   # Global
@@ -923,7 +927,16 @@ endif()
 # LuaJIT (Scripting Support)
 # ==========================
 if(FLB_LUAJIT)
-  include(cmake/luajit.cmake)
+  if(FLB_PREFER_SYSTEM_LIB_LUAJIT)
+    find_package(PkgConfig)
+    pkg_check_modules(LUAJIT luajit>=2.1.0)
+  endif()
+  if(LUAJIT_FOUND)
+    include_directories(${LUAJIT_INCLUDE_DIRS})
+    link_directories(${LUAJIT_LIBRARY_DIRS})
+  else()
+    include(cmake/luajit.cmake)
+  endif()
   FLB_DEFINITION(FLB_HAVE_LUAJIT)
 endif()
 
diff --git a/cmake/headers.cmake b/cmake/headers.cmake
index 45a1394ca7f..500c4c3b947 100755
--- a/cmake/headers.cmake
+++ b/cmake/headers.cmake
@@ -22,10 +22,6 @@ include_directories(
   ${FLB_PATH_ROOT_SOURCE}/${FLB_PATH_LIB_CHUNKIO}/include
   ${CMAKE_CURRENT_BINARY_DIR}/lib/chunkio/include
 
-  # LuaJIT
-  ${FLB_PATH_ROOT_SOURCE}/${FLB_PATH_LIB_LUAJIT}/src
-  ${CMAKE_CURRENT_BINARY_DIR}/lib/luajit-cmake
-
   ${FLB_PATH_ROOT_SOURCE}/${FLB_PATH_LIB_MONKEY}/include
   ${FLB_PATH_ROOT_SOURCE}/${FLB_PATH_LIB_MONKEY}/include/monkey
   ${FLB_PATH_ROOT_SOURCE}/${FLB_PATH_LIB_MBEDTLS}/include
diff --git a/cmake/luajit.cmake b/cmake/luajit.cmake
index b6774eb4452..f00b843cb35 100644
--- a/cmake/luajit.cmake
+++ b/cmake/luajit.cmake
@@ -1,4 +1,9 @@
 # luajit cmake
 option(LUAJIT_DIR "Path of LuaJIT 2.1 source dir" ON)
 set(LUAJIT_DIR ${FLB_PATH_ROOT_SOURCE}/${FLB_PATH_LIB_LUAJIT})
+include_directories(
+  ${LUAJIT_DIR}/src
+  ${CMAKE_CURRENT_BINARY_DIR}/lib/luajit-cmake
+)
 add_subdirectory("lib/luajit-cmake")
+set(LUAJIT_LIBRARIES "libluajit")
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 593e9865bc4..084f2c57d52 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -223,7 +223,7 @@ endif()
 if(FLB_LUAJIT)
   set(extra_libs
     ${extra_libs}
-    "libluajit")
+    ${LUAJIT_LIBRARIES})
 endif()
 
 if(FLB_SQLDB)