Ship en_US hunspell dictionaries on Windows and OSX

For now, this uses the same OpenOffice dictionaries that were used in
previous official releases, downloaded from
https://sourceforge.net/projects/openofficeorg.mirror/files/contrib/dictionaries/
In the future this could be updated to some newer dictionary like
SCOWL's.

Fixes #21.

packages/win_installer/fragment_spelling.iss

@@ -1,5 +1,5 @@
 ; This file declares all installables related to spell checking and thesaurii in Aegisub
 
 [Files]
-Source: {#DEPS_DIR}\dictionaries\en_US.aff; DestDir: {app}\dictionaries; Flags: skipifsourcedoesntexist ignoreversion
-Source: {#DEPS_DIR}\dictionaries\en_US.dic; DestDir: {app}\dictionaries; Flags: skipifsourcedoesntexist ignoreversion
+Source: {#DEPS_DIR}\dictionaries\en_US.aff; DestDir: {app}\dictionaries; Flags: ignoreversion; Components: dictionaries/en_US
+Source: {#DEPS_DIR}\dictionaries\en_US.dic; DestDir: {app}\dictionaries; Flags: ignoreversion; Components: dictionaries/en_US

packages/win_installer/portable/create-portable.ps1

@@ -51,6 +51,9 @@ Copy-New-Item $InstallerDir\bin\aegisub.exe  $PortableOutputDir
 
 Write-Output 'Copying - translations'
 Copy-New-Items "$InstallerDir\share\locale\*"  "$PortableOutputDir\locale" -Recurse
+Write-Output 'Copying - dictionaries'
+Copy-New-Item $InstallerDepsDir\dictionaries\en_US.aff  $PortableOutputDir\dictionaries
+Copy-New-Item $InstallerDepsDir\dictionaries\en_US.dic  $PortableOutputDir\dictionaries
 Write-Output 'Copying - codecs'
 Write-Output 'Copying - codecs\Avisynth'
 Copy-New-Item $InstallerDepsDir\AvisynthPlus64\x64\system\DevIL.dll  $PortableOutputDir

tools/osx-bundle.sh

@@ -61,7 +61,12 @@ echo "---- Copying dictionaries ----"
 if test -f "${DICT_DIR}"; then
   cp -v "${DICT_DIR}/*" "${PKG_DIR}/Contents/SharedSupport/dictionaries"
 else
-  echo "Specified dictionary directory ${DICT_DIR} not found!"
+  echo "Specified dictionary directory ${DICT_DIR} not found. Downloading dictionaries:"
+  mkdir "${BUILD_DIR}/dictionaries"
+  curl -L "https://downloads.sourceforge.net/project/openofficeorg.mirror/contrib/dictionaries/en_US.zip" -o "${BUILD_DIR}/dictionaries/en_US.zip"
+  unzip "${BUILD_DIR}/dictionaries/en_US.zip" -d "${BUILD_DIR}/dictionaries"
+  cp -v "${BUILD_DIR}/dictionaries/en_US.aff" "${PKG_DIR}/Contents/SharedSupport/dictionaries"
+  cp -v "${BUILD_DIR}/dictionaries/en_US.dic" "${PKG_DIR}/Contents/SharedSupport/dictionaries"
 fi
 
 echo

tools/win-installer-setup.ps1

@@ -79,7 +79,14 @@ if (!(Test-Path VC_redist)) {
 	Invoke-WebRequest https://aka.ms/vs/17/release/VC_redist.x64.exe -OutFile "$redistDir\VC_redist.x64.exe" -UseBasicParsing
 }
 
-# TODO dictionaries
+# dictionaries
+if (!(Test-Path dictionaries)) {
+	New-Item -ItemType Directory dictionaries
+	[Net.ServicePointManager]::SecurityProtocol = "Tls12" 	# Needed since otherwise downloading fails in some places like on the GitHub CI: https://stackoverflow.com/a/66614041/4730656
+	Invoke-WebRequest https://downloads.sourceforge.net/project/openofficeorg.mirror/contrib/dictionaries/en_US.zip -UserAgent "Wget" -OutFile en_US.zip -UseBasicParsing
+	Expand-Archive -LiteralPath en_US.zip -DestinationPath dictionaries
+	Remove-Item en_US.zip
+}
 
 # localization
 Set-Location $BuildRoot