Fix windows library filename (#655)

* Fix library name on Windows

* The name was accidentally changed to sys.dll in a previous refactor
* Also rename `get_sysimg_file` -> `get_library_filename`.  It used to
  be used to get the sysimg filename for `create_app` and `create_lib`,
  but now it's only used by `create_lib`.

* Remove extra whitespace

Author: kmsquire

src/PackageCompiler.jl

@@ -38,7 +38,7 @@ end
 
 function bitflag()
     Sys.ARCH === :i686   ? `-m32` :
-    Sys.ARCH === :x86_64 ? `-m64` : 
+    Sys.ARCH === :x86_64 ? `-m64` :
         ``
 end
 
@@ -151,8 +151,8 @@ function run_compiler(cmd::Cmd; cplusplus::Bool=false)
                     break
                 end
             end
-        end 
-        found_compiler || error("could not find a compiler, looked for ", 
+        end
+        found_compiler || error("could not find a compiler, looked for ",
             join(((cplusplus ? compilers_cpp : ())..., compilers_c...), ", ", " and "))
     end
     if path !== nothing
@@ -187,7 +187,7 @@ function create_fresh_base_sysimage(stdlibs::Vector{String}; cpu_target::String)
     tmp_sys_ji = joinpath(tmp, "sys.ji")
     compiler_source_path = joinpath(base_dir, "compiler", "compiler.jl")
 
-    spinner = TerminalSpinners.Spinner(msg = "PackageCompiler: compiling base system image (incremental=false)") 
+    spinner = TerminalSpinners.Spinner(msg = "PackageCompiler: compiling base system image (incremental=false)")
     TerminalSpinners.@spin spinner begin
         cd(base_dir) do
             # Create corecompiler.ji
@@ -348,11 +348,11 @@ function create_sysimg_object_file(object_file::String,
     outputo_file = tempname()
     write(outputo_file, julia_code)
     # Read the input via stdin to avoid hitting the maximum command line limit
-   
+
     cmd = `$(get_julia_cmd()) --cpu-target=$cpu_target -O3 $sysimage_build_args
                               --sysimage=$base_sysimage --project=$project --output-o=$(object_file) $outputo_file`
     @debug "running $cmd"
-    spinner = TerminalSpinners.Spinner(msg = "PackageCompiler: compiling incremental system image") 
+    spinner = TerminalSpinners.Spinner(msg = "PackageCompiler: compiling incremental system image")
     TerminalSpinners.@spin spinner run(cmd)
     return
 end
@@ -453,7 +453,7 @@ function create_sysimage(packages::Union{Nothing, Symbol, Vector{String}, Vector
         if base_sysimage !== nothing
             error("cannot specify `base_sysimage`  when `incremental=false`")
         end
-        sysimage_stdlibs = filter_stdlibs ? gather_stdlibs_project(ctx) : stdlibs_in_sysimage()    
+        sysimage_stdlibs = filter_stdlibs ? gather_stdlibs_project(ctx) : stdlibs_in_sysimage()
         base_sysimage = create_fresh_base_sysimage(sysimage_stdlibs; cpu_target)
     else
         base_sysimage = something(base_sysimage, unsafe_string(Base.JLOptions().image_file))
@@ -503,7 +503,7 @@ function create_sysimage(packages::Union{Nothing, Symbol, Vector{String}, Vector
 
     # Create the sysimage
     object_file = tempname() * ".o"
-    
+
     create_sysimg_object_file(object_file, packages, packages_sysimg;
                             project,
                             base_sysimage,
@@ -541,7 +541,7 @@ function create_sysimg_from_object_file(object_files::Vector{String},
                                         version,
                                         compat_level::String,
                                         soname::Union{Nothing, String})
- 
+
     if soname === nothing && (Sys.isunix() && !Sys.isapple())
         soname = basename(sysimage_path)
     end
@@ -860,7 +860,7 @@ function create_library(package_dir::String,
                         sysimage_build_args::Cmd=``,
                         include_transitive_dependencies::Bool=true)
 
-                            
+
     warn_official()
 
     julia_init_h_file = String(DEFAULT_JULIA_INIT_HEADER)
@@ -886,9 +886,9 @@ function create_library(package_dir::String,
 
     lib_dir = Sys.iswindows() ? joinpath(dest_dir, "bin") : joinpath(dest_dir, "lib")
 
-    sysimg_file = get_sysimg_file(lib_name; version)
+    sysimg_file = get_library_filename(lib_name; version)
     sysimg_path = joinpath(lib_dir, sysimg_file)
-    compat_file = get_sysimg_file(lib_name; version, compat_level)
+    compat_file = get_library_filename(lib_name; version, compat_level)
     soname = (Sys.isunix() && !Sys.isapple()) ? compat_file : nothing
 
     create_sysimage_workaround(ctx, sysimg_path, precompile_execution_file,
@@ -898,7 +898,7 @@ function create_library(package_dir::String,
 
     if version !== nothing && Sys.isunix()
         cd(dirname(sysimg_path)) do
-            base_file = get_sysimg_file(lib_name)
+            base_file = get_library_filename(lib_name)
             @debug "creating symlinks for $compat_file and $base_file"
             symlink(sysimg_file, compat_file)
             symlink(sysimg_file, base_file)
@@ -915,12 +915,12 @@ function get_compat_version_str(version::VersionNumber, level::String)
         error("Unknown level: $level")
 end
 
-function get_sysimg_file(name::String;
-                         version::Union{VersionNumber, Nothing}=nothing,
-                         compat_level::String="patch")
+function get_library_filename(name::String;
+                              version::Union{VersionNumber, Nothing}=nothing,
+                              compat_level::String="patch")
 
     dlext = Libdl.dlext
-    Sys.iswindows() && return "sys.$dlext"
+    Sys.iswindows() && return "$name.$dlext"
 
     # For libraries on Unix/Apple, make sure the name starts with "lib"
     if !startswith(name, "lib")
@@ -930,7 +930,7 @@ function get_sysimg_file(name::String;
     version === nothing && return "$name.$dlext"
 
     version = get_compat_version_str(version, compat_level)
-    
+
     sysimg_file = (
         Sys.isapple() ? "$name.$version.$dlext" :  # libname.1.2.3.dylib
         Sys.isunix() ? "$name.$dlext.$version" :   # libname.so.1.2.3