Problem: no CI for cygwin

Solution: add cygwin build

appveyor.yml

@@ -65,6 +65,10 @@ environment:
       CMAKE_GENERATOR: "Visual Studio 15 2017"
       MSVCVERSION: "v141"
       MSVCYEAR: "vs2017"
+    - platform: cygwin64
+      WITH_LIBSODIUM: OFF
+      ENABLE_CURVE: ON
+      CMAKE_GENERATOR: "Unix Makefiles"
 
 matrix:
   fast_finish: false
@@ -83,8 +87,11 @@ init:
 
 cache:
     - C:\projects\libsodium
+    - C:\cygwin64\var\cache\setup
 
 install:
+  - cmd: if "%Platform%"=="cygwin64" C:\cygwin64\setup-x86_64.exe --quiet-mode --no-shortcuts --upgrade-also --packages cmake,cygwin-devel,gcc-g++,libncurses-devel,make,pkg-config
+  - cmd: if "%Platform%"=="cygwin64" set PATH=C:\cygwin64\bin;%PATH%
   - cmd: if "%Platform%"=="x64" set "CMAKE_GENERATOR=%CMAKE_GENERATOR% Win64"
   - cmd: echo "Generator='%CMAKE_GENERATOR%'"
   - cmd: echo "Platform='%Platform%'"
@@ -113,15 +120,26 @@ before_build:
   # - cmd: set BUILDLOG="%LIBZMQ_SRCDIR%\build.log"
   - cmd: md "%LIBZMQ_BUILDDIR%"
   - cd "%LIBZMQ_BUILDDIR%"
-  - cmd: cmake -D CMAKE_INCLUDE_PATH="%SODIUM_INCLUDE_DIR%" -D CMAKE_LIBRARY_PATH="%SODIUM_LIBRARY_DIR%" -D WITH_LIBSODIUM="%WITH_LIBSODIUM%" -D ENABLE_DRAFTS="%ENABLE_DRAFTS%" -D ENABLE_ANALYSIS="%ENABLE_ANALYSIS%" -D ENABLE_CURVE="%ENABLE_CURVE%" -D API_POLLER="%API_POLLER%" -D POLLER="%POLLER%" -D CMAKE_C_FLAGS_RELEASE="/MT" -D CMAKE_C_FLAGS_DEBUG="/MTd" -D WITH_LIBSODIUM="%WITH_LIBSODIUM%" -G "%CMAKE_GENERATOR%" "%APPVEYOR_BUILD_FOLDER%"
+  - cmd: if "%PLATFORM%" ==  "cygwin64" set APPVEYOR_BUILD_FOLDER=/cygdrive/C/projects/libzmq
+  - cmd: if "%PLATFORM%" NEQ "cygwin64" set EXTRA_FLAGS='-D CMAKE_C_FLAGS_RELEASE="/MT" -D CMAKE_C_FLAGS_DEBUG="/MTd"'
+  - cmd: cmake -D CMAKE_INCLUDE_PATH="%SODIUM_INCLUDE_DIR%" -D CMAKE_LIBRARY_PATH="%SODIUM_LIBRARY_DIR%" -D WITH_LIBSODIUM="%WITH_LIBSODIUM%" -D ENABLE_DRAFTS="%ENABLE_DRAFTS%" -D ENABLE_ANALYSIS="%ENABLE_ANALYSIS%" -D ENABLE_CURVE="%ENABLE_CURVE%" -D API_POLLER="%API_POLLER%" -D POLLER="%POLLER%" %EXTRA_FLAGS% -D WITH_LIBSODIUM="%WITH_LIBSODIUM%" -D LIBZMQ_WERROR="ON" -G "%CMAKE_GENERATOR%" "%APPVEYOR_BUILD_FOLDER%"
   - cmd: cd "%LIBZMQ_SRCDIR%"
 
 build_script:
-  - cmd: if "%MSVCYEAR%"=="vs2008" (
-            cmake --build %LIBZMQ_BUILDDIR% --config %configuration% --target install
-         ) else (
-            cmake --build %LIBZMQ_BUILDDIR% --config %configuration% --target install -- -verbosity:Minimal -maxcpucount -logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll"
+  - cmd: set verbosity=Minimal
+  - cmd: if "%MSVCYEAR%"=="vs2008" set verbosity=Normal
+  - cmd: if "%MSVCYEAR%"=="vs2008" set path=C:\Windows\Microsoft.NET\Framework\v3.5;%path% 
+  - cmd: cd "%LIBZMQ_BUILDDIR%"
+  - cmd: if "%PLATFORM%" NEQ "cygwin64" (
+            if "%MSVCYEAR%"=="vs2008" (
+                cmake --build %LIBZMQ_BUILDDIR% --config %configuration% --target install
+            ) else (
+                cmake --build %LIBZMQ_BUILDDIR% --config %configuration% --target install -- -verbosity:Minimal -maxcpucount -logger:"C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll"
+            )
          )
+  - cmd: if "%PLATFORM%" ==  "cygwin64" cmake --build . -- -j5
+  # TODO this is definitely not the optimal place&way to do this
+  - cmd: if "%PLATFORM%" ==  "cygwin64" cp lib/libzmq-5.dll bin
 
 # TODO this does not work with sonarcloud.io, as it misses the sonar-cxx plugin
 # build_script: