Allow the create_app function to accept and propagate the script::Union{Nothing, String} kwarg (#788)

Author: DilumAluthge

src/PackageCompiler.jl

@@ -770,6 +770,8 @@ compiler (can also include extra arguments to the compiler, like `-g`).
 
 - `sysimage_build_args::Cmd`: A set of command line options that is used in the Julia process building the sysimage,
   for example `-O1 --check-bounds=yes`.
+
+- `script::String`: Path to a file that gets executed in the `--output-o` process.
 """
 function create_app(package_dir::String,
                     app_dir::String;
@@ -783,7 +785,8 @@ function create_app(package_dir::String,
                     cpu_target::String=default_app_cpu_target(),
                     include_lazy_artifacts::Bool=false,
                     sysimage_build_args::Cmd=``,
-                    include_transitive_dependencies::Bool=true)
+                    include_transitive_dependencies::Bool=true,
+                    script::Union{Nothing, String}=nothing)
     warn_official()
     if filter_stdlibs && incremental
         error("must use `incremental=false` to use `filter_stdlibs=true`")
@@ -828,7 +831,8 @@ function create_app(package_dir::String,
                     cpu_target,
                     sysimage_build_args,
                     include_transitive_dependencies,
-                    extra_precompiles = join(precompiles, "\n"))
+                    extra_precompiles = join(precompiles, "\n"),
+                    script)
 
     for (app_name, julia_main) in executables
         create_executable_from_sysimg(joinpath(app_dir, "bin", app_name), c_driver_program, string(package_name, ".", julia_main))