enable important_pkg on OSX (nim-lang#13954)

* enable important_pkg on OSX

* disable some important_packages on OSX

* fixup

* enable nigui by installing dependency

azure-pipelines.yml

@@ -34,6 +34,10 @@ jobs:
         vmImage: 'ubuntu-16.04'
         CPU: amd64
         NIM_TEST_PACKAGES: true
+      OSX_amd64_pkg:
+        vmImage: 'macOS-10.15'
+        CPU: amd64
+        NIM_TEST_PACKAGES: true
 
   pool:
     vmImage: $(vmImage)

testament/important_packages.nim

@@ -1,3 +1,4 @@
+import os
 
 template pkg(name: string; hasDeps = false; cmd = "nimble test"; url = ""): untyped =
   packages.add((name, cmd, hasDeps, url))
@@ -17,7 +18,8 @@ pkg "c2nim", false, "nim c testsuite/tester.nim"
 pkg "cascade"
 pkg "chroma"
 pkg "chronicles", true, "nim c -o:chr -r chronicles.nim"
-pkg "chronos", true
+when not defined(osx): # testdatagram.nim(560, 54): Check failed
+  pkg "chronos", true
 pkg "cligen", false, "nim c -o:cligenn -r cligen.nim"
 pkg "coco", true
 pkg "combparser"
@@ -46,7 +48,13 @@ pkg "nake", false, "nim c nakefile.nim"
 pkg "neo", true, "nim c -d:blas=openblas tests/all.nim"
 # pkg "nico", true
 pkg "nicy", false, "nim c src/nicy.nim"
+
+when defined(osx):
+  # do this more generally by installing non-nim dependencies automatically
+  # as specified in nimble file
+  doAssert execShellCmd("brew install gtk+3") == 0
 pkg "nigui", false, "nim c -o:niguii -r src/nigui.nim"
+
 pkg "nimcrypto", false, "nim c -r tests/testall.nim"
 pkg "NimData", true, "nim c -o:nimdataa src/nimdata.nim"
 pkg "nimes", true, "nim c src/nimes.nim"