Clear deprecation warnings

This fix clears deprecation warnings related to Nim's HashSet
procedures. There were two types of warnings which have been fixed:

 - Warning: Deprecated since v0.20, use 'initHashSet'; initSet is
   deprecated [Deprecated]

 - Warning: Deprecated since v0.20, use 'toHashSet'; toSet is
   deprecated [Deprecated]

Backward compatibility with older Nim versions is also implemented.

Related to #680

src/nimble.nim

@@ -94,7 +94,7 @@ proc copyFilesRec(origDir, currentDir, dest: string,
   ## Copies all the required files, skips files specified in the .nimble file
   ## (PackageInfo).
   ## Returns a list of filepaths to files which have been installed.
-  result = initSet[string]()
+  result = initHashSet[string]()
   let whitelistMode =
           pkgInfo.installDirs.len != 0 or
           pkgInfo.installFiles.len != 0 or
@@ -373,7 +373,7 @@ proc installFromDir(dir: string, requestedVer: VersionRange, options: Options,
 
   createDir(pkgDestDir)
   # Copy this package's files based on the preferences specified in PkgInfo.
-  var filesInstalled = initSet[string]()
+  var filesInstalled = initHashSet[string]()
   iterInstallFiles(realDir, pkgInfo, options,
     proc (file: string) =
       createDir(changeRoot(realDir, pkgDestDir, file.splitFile.dir))
@@ -386,7 +386,7 @@ proc installFromDir(dir: string, requestedVer: VersionRange, options: Options,
                         pkgInfo.myPath)
   filesInstalled.incl copyFileD(pkgInfo.myPath, dest)
 
-  var binariesInstalled = initSet[string]()
+  var binariesInstalled = initHashSet[string]()
   if pkgInfo.bin.len > 0:
     # Make sure ~/.nimble/bin directory is created.
     createDir(binDir)

src/nimblepkg/cli.nim

@@ -15,6 +15,9 @@
 import terminal, sets, strutils
 import version
 
+when not declared(initHashSet):
+  import common
+
 type
   CLI* = ref object
     level: Priority
@@ -46,7 +49,7 @@ const
 proc newCLI(): CLI =
   result = CLI(
     level: HighPriority,
-    warnings: initSet[(string, string)](),
+    warnings: initHashSet[(string, string)](),
     suppressionCount: 0,
     showColor: true,
     suppressMessages: false

src/nimblepkg/common.nim

@@ -63,3 +63,15 @@ when not defined(nimscript):
 
 const
   nimbleVersion* = "0.10.2"
+
+when not declared(initHashSet):
+  import sets
+
+  template initHashSet*[A](initialSize = 64): HashSet[A] =
+    initSet[A](initialSize)
+
+when not declared(toHashSet):
+  import sets
+
+  template toHashSet*[A](keys: openArray[A]): HashSet[A] =
+    toSet(keys)

src/nimblepkg/packageinfo.nim

@@ -277,7 +277,7 @@ proc getPackage*(pkg: string, options: Options, resPkg: var Package): bool =
 proc getPackageList*(options: Options): seq[Package] =
   ## Returns the list of packages found in the downloaded packages.json files.
   result = @[]
-  var namesAdded = initSet[string]()
+  var namesAdded = initHashSet[string]()
   for name, list in options.config.packageLists:
     let packages = readPackageList(name, options)
     for p in packages:

src/nimblepkg/packageinstaller.nim

@@ -5,6 +5,9 @@ import os, strutils, sets, json
 # Local imports
 import version, cli, options, tools
 
+when not declared(initHashSet) or not declared(toHashSet):
+  import common
+
 when defined(windows):
   # This is just for Win XP support.
   # TODO: Drop XP support?
@@ -103,4 +106,4 @@ proc saveNimbleMeta*(pkgDestDir, pkgDir, vcsRevision, nimbleLinkPath: string) =
   ## pkgDir - The directory where the original package files are.
   ##          For example: ~/projects/jester/
   saveNimbleMeta(pkgDestDir, "file://" & pkgDir, vcsRevision,
-                 toSet[string]([nimbleLinkPath]), initSet[string](), true)
+                 toHashSet[string]([nimbleLinkPath]), initHashSet[string](), true)