CMake,WSDG: Remove Cygwin support

Declare Cygwin as unsupported and remove all supporting code. Simplify
some Chocolatey notes in the WSDG.

Remove FindPerl.cmake as it only existed to force use of Wireshark's
bundled FindCygwin.cmake (bug 13922). FindXSLTPROC.cmake special
handling for Cygwin was also removed, in theory this could cause issues
when the PATH contains a Cygwin xsltproc, but it's unsupported anyway.

Change-Id: Iabfac2b4a9fd930530505d27bdba618bdb8f7f34
Reviewed-on: https://code.wireshark.org/review/31452
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>

2 files changed, 9 insertions, 110 deletions

diff --git a/docbook/wsdg_src/WSDG_chapter_quick_setup.asciidoc b/docbook/wsdg_src/WSDG_chapter_quick_setup.asciidoc
index ea7deecf5c..d99d0f9317 100644
--- a/docbook/wsdg_src/WSDG_chapter_quick_setup.asciidoc
+++ b/docbook/wsdg_src/WSDG_chapter_quick_setup.asciidoc
@@ -117,12 +117,12 @@ upgrade Qt to newer versions.
 https://chocolatey.org/[Chocolatey] is a native package manager for
 Windows. There are https://chocolatey.org/packages[packages] for most of
 the software listed below. Along with traditional Windows packages it
-supports the Python Package Index and Cygwin.
+supports the Python Package Index.
 
-Chocolatey tends to install packages into its own path (%ChocolateyInstall%).
-In most cases this is OK, but in some instances (Python in particular)
-this might not be what you want. You can install Chocolatey packages
-using the command `choco install`.
+Chocolatey tends to install packages into its own path (%ChocolateyInstall%),
+although packages are free to use their own preferences (Python for example is
+installed to `C:\Python37`). You can install Chocolatey packages using the
+command `choco install` (or its shorthand, `cinst`).
 
 [source,cmd]
 ----
@@ -130,70 +130,7 @@ using the command `choco install`.
 > choco install -y winflexbison
 > rem Git, CMake, Perl, Python, etc are also required, but can be installed
 > rem via their respective installation packages.
-> choco install -y git cmake
-> rem Choose one of Strawberry...
-> choco install -y strawberryperl
-> rem ...or ActiveState Perl
-> choco install -y activeperl
-> rem This will likely install Python in a non-standard location, but
-> rem should otherwise work.
-> choco install -y python3
-----
-
-[[ChSetupCygwin]]
-
-==== Optional: Install Cygwin
-
-On 32-bit Windows, http://www.cygwin.com/setup-x86.exe[download the
-32-bit Cygwin installer] and start it. On 64-bit Windows,
-http://www.cygwin.com/setup-x86_64.exe[download the 64-bit Cygwin
-installer] and start it.
-
-[NOTE]
-.Cygwin is no longer required
-====
-In the past the Wireshark development toolchain depended on Cygwin, but
-it it no longer required. Although you can often use the Cygwin version
-of a particular tool for Wireshark development that's not always the
-case.
-====
-
-At the "Select Packages" page, you'll need to select
-some additional packages which are not installed by default.
-Navigate to the required Category/Package row and, if the package
-has a "Skip" item in the "New" column, click on the "Skip" item
-so it shows a version number for:
-
-* Devel/bison (or install Win flex-bison -- see Chocolatey above)
-
-* Devel/flex (or install Win flex-bison -- see Chocolatey above)
-
-* Devel/git (recommended, but it's also available via Chocolatey -- see the Git discussion below)
-
-* Interpreters/perl
-
-* Utils/patch (only if needed) (may be Devel/patch instead)
-
-* Text/docbook-xml45 (only needed if you're building the documenation)
-
-After clicking the btn:[Next] button several times, the setup
-will then download and install the selected packages (this
-may take a while).
-
-Alternatively you can install Cygwin and its packages using Chocolatey:
-
-----
-PS$>choco install -y cygwin
-PS$>choco install -y cyg-get
-----
-//PS$>choco install sed [...] -source cygwin
-
-Chocolatey installs Cygwin in _C:\tools\cygwin_ by default.
-
-You can directly download packages via `cyg-get`
-
-----
-PS$>cyg-get docbook-xml45 [...]
+> choco install -y git cmake strawberryperl python3
 ----
 
 [[ChSetupPython]]
@@ -203,10 +140,6 @@ PS$>cyg-get docbook-xml45 [...]
 Get a Python 3.x installer from https://python.org/download/[] and
 install Python into the default location (_C:\Python37_).
 
-Why is this recommended? Cygwin’s _/usr/bin/python_ is a Cygwin-specific
-symbolic link which cannot be run from Windows. The native package is faster
-as well.
-
 Alternatively you can install Python using Chocolatey:
 
 ----
@@ -384,14 +317,6 @@ Set the following environment variables, using paths and values suitable for you
 > set WIRESHARK_VERSION_EXTRA=-YourExtraVersionInfo
 ----
 
-If your Cygwin installation path is not automatically detected by CMake,
-you can explicitly specify it with the following environment variable:
-
-----
-> rem Chocolatey installs Cygwin in an odd location
-> set WIRESHARK_CYGWIN_INSTALL_PATH=C:\ProgramData\chocolatey\lib\Cygwin\tools\cygwin
-----
-
 If you are using a version of Visual Studio earlier than VS2017 then you must set an additional env var,
 e.g. for VS2019 set the following:
 ----
diff --git a/docbook/wsdg_src/WSDG_chapter_tools.asciidoc b/docbook/wsdg_src/WSDG_chapter_tools.asciidoc
index 5f1388ef35..5a21265a21 100644
--- a/docbook/wsdg_src/WSDG_chapter_tools.asciidoc
+++ b/docbook/wsdg_src/WSDG_chapter_tools.asciidoc
@@ -17,8 +17,7 @@ as Linux, but Windows ports are also available. Therefore the tools are
 available in different "flavours":
 
 * UNIX and UNIX-like platforms: The tools should be commonly available
-  on the supported UNIX and UNIX-like platforms and for Windows
-  platforms by using an emulation layer such as Cygwin.
+  on the supported UNIX and UNIX-like platforms. Cygwin is unsupported.
 * Windows native: Some tools are available as native Windows tools, no
   special emulation is required.  Many of these tools can be installed
   (and updated) using http://chocolatey.org[Chocolatey], a Windows
@@ -70,29 +69,6 @@ _C:\ProgramData\chocolatey_ or _C:\Tools_. If you want to avoid this
 behavior you'll probabaly want to install Python using the packages from
 python.org.
 
-[[ChToolsCygwin]]
-
-=== Windows: Cygwin
-
-Cygwin provides a lot of UNIX based tools on the Windows platform. It
-uses a UNIX emulation layer which might be a bit slower compared to the
-native Windows tools, but at an acceptable level. The installation and
-update is pretty easy and done through a single utility, _setup-x86.exe_
-for 32-bit Windows and _setup-x86_64.exe_ for 64-bit Windows. However,
-it can also be problematic. Cygwin utilities have a non-standard view of
-the filesystem, and sometimes things don't work as expected. For
-example, many files in _/usr/bin_ are symlinks which can't be run
-directly from Windows.
-
-[NOTE]
-.Cygwin is no longer required
-====
-In the past the Wireshark development toolchain depended on Cygwin, but
-it it no longer required. Although you can often use the Cygwin version
-of a particular tool for Wireshark development that's not always the
-case.
-====
-
 [[ChToolsCMake]]
 
 === CMake
@@ -142,7 +118,7 @@ optional libraries have xxx_INCLUDE_DIR and xxx_LIB flags that let you
 control their discovery.
 
 
--DPYTHON_EXECUTABLE=c:/Python36/python:: Force the Python path. Useful on Windows since Cygwin’s _/usr/bin/python_ is a symlink.
+-DPYTHON_EXECUTABLE=c:/Python36/python:: Force the Python path.
 
 -DENABLE_APPLICATION_BUNDLE=OFF:: Disable building an application bundle (Wireshark.app) on macOS
 
@@ -666,8 +642,6 @@ Python 3.4 and later is required. Python 2.7 is no longer supported.
 
 Python is either included or available as a package on most UNIX-like platforms.
 Windows packages and source are available at https://python.org/download/[].
-The Cygwin Python package is *not* recommended since _/usr/bin/python_ is
-a symbolic link, which causes confusion outside Cygwin.
 
 You can also use Chocolatey to install Python:
 
@@ -843,7 +817,7 @@ https://chocolatey.org/[Chocolatey] package. Note that the executable is named
 _win_bison_.
 
 Native packages are available from other sources such as
-http://gnuwin32.sourceforge.net/packages/bison.htm[GnuWin] and Cygwin.
+http://gnuwin32.sourceforge.net/packages/bison.htm[GnuWin].
 They aren't officially supported but _should_ work.
 
 [[ChToolsFlex]]