reason.add_interface_library.help

reason_add_interface_library: reasonable add interface/header-only library
params:
  - TARGET      (STRING): The target name
  - INC_DIRS    (LIST)  : include directories
  - HDR_SRCS    (LIST)  : the header sources (if listed, use them as `target_source`,
                                              else recursive find all files in 'INC_DIRS')
  - DEFINES     (LIST)  : Extra compile definitions for target (optional)
description:
  'reason_add_interface_library' will help you create header-only library as target "${TARGET}"
  it automatically pulls the include directory if is LINK-ed as dependency with 'target_link_libraries'
  or reason's links.
example:
  1. Simply use all the files in INC_DIRS
     add_interface_library(TARGET "foo" INC_DIRS "include")
  2. Specify the header files
     add_interface_library(TARGET "foo" INC_DIRS "include"
                           HDR_SRCS "include/foo/hdr1.hpp" "include/foo/hdr2.hpp")