fluent-bit: fix build on darwin

pkgs/tools/misc/fluent-bit/default.nix

@@ -13,6 +13,8 @@ stdenv.mkDerivation rec {
 
   nativeBuildInputs = [ cmake flex bison ];
 
+  patches = [ ./fix-luajit-darwin.patch ];
+
   postPatch = ''
     substituteInPlace src/CMakeLists.txt \
       --replace /lib/systemd $out/lib/systemd

pkgs/tools/misc/fluent-bit/fix-luajit-darwin.patch

@@ -0,0 +1,14 @@
+diff -Naur fluent-bit.old/cmake/luajit.cmake fluent-bit.new/cmake/luajit.cmake
+--- fluent-bit.old/cmake/luajit.cmake
++++ fluent-bit.new/cmake/luajit.cmake
+@@ -11,10 +11,6 @@
+ set(LUAJIT_SRC ${CMAKE_CURRENT_SOURCE_DIR}/${FLB_PATH_LIB_LUAJIT})
+ set(LUAJIT_DEST ${CMAKE_CURRENT_BINARY_DIR})
+ 
+-if (CMAKE_SYSTEM_NAME MATCHES "Darwin")
+-  set(CFLAGS "${CFLAGS} -isysroot ${CMAKE_OSX_SYSROOT}")
+-endif()
+-
+ # luajit (UNIX)
+ # =============
+ ExternalProject_Add(luajit