Merge: Interpreter FFI: support the pkgconfig annotation

Pull-Request: #1980
Reviewed-by: Jean Privat <jean@pryen.org>

diff --cc src/interpreter/dynamic_loading_ffi/on_demand_compiler.nit
index ab9e845,e41e743..e826f05
--- 1/src/interpreter/dynamic_loading_ffi/on_demand_compiler.nit
--- 2/src/interpreter/dynamic_loading_ffi/on_demand_compiler.nit
+++ b/src/interpreter/dynamic_loading_ffi/on_demand_compiler.nit
@@@ -20,15 -20,7 +20,16 @@@ import c_tool
  import nitni
  import ffi
  import naive_interpreter
+ import pkgconfig
 +import debugger_socket # To linearize `ToolContext::init`
 +
 +redef class ToolContext
 +
 +      # --compile-dir
 +      var opt_compile_dir = new OptionString("Directory used to generate temporary files", "--compile-dir")
 +
 +      init do option_context.add_option opt_compile_dir
 +end
  
  redef class AMethPropdef
        # Does this method definition use the FFI and is it supported by the interpreter?