Added NetworkBSD build flag to deal with Network.BSD moving to a new package.

Like with the network-uri split, cabal will automatically turn off the flag
when building with an old network.

I have not tested building with the new network-3.0.0.0 yet; several
other dependencies including aws are still pinned on network-2.*

CHANGELOG

@@ -25,6 +25,8 @@ git-annex (7.20190130) UNRELEASED; urgency=medium
     urls get truncated on those. Fail in a better way in this case,
     and avoid failing when removing such files from the export, so
     after the user has renamed the problem files the export will succeed.
+  * Added NetworkBSD build flag to deal with Network.BSD moving to a new
+    package.
 
  -- Joey Hess <id@joeyh.name>  Wed, 30 Jan 2019 12:30:22 -0400
 

git-annex.cabal

@@ -284,6 +284,10 @@ Flag DebugLocks
 Flag Dbus
   Description: Enable dbus support
 
+Flag NetworkBSD
+  Description: Build with network-3.0 which split out network-bsd
+  Default: True
+
 source-repository head
   type: git
   location: git://git-annex.branchable.com/
@@ -297,7 +301,6 @@ Executable git-annex
   Main-Is: git-annex.hs
   Build-Depends:
    base (>= 4.9 && < 5.0),
-   network (>= 2.6.3.0),
    network-uri (>= 2.6),
    optparse-applicative (>= 0.11.0),
    containers (>= 0.5.7.1),
@@ -392,6 +395,11 @@ Executable git-annex
   else
     Build-Depends: unix (>= 2.7.2)
 
+  if flag(NetworkBSD)
+    Build-Depends: network-bsd, network (>= 3.0.0.0)
+  else
+    Build-Depends: network (< 3.0.0.0), network (>= 2.6.3.0)
+
   if flag(S3)
     Build-Depends: aws (>= 0.9.2)
     CPP-Options: -DWITH_S3

stack-lts-9.9.yaml

@@ -11,6 +11,7 @@ flags:
     dbus: false
     debuglocks: false
     benchmark: false
+    networkbsd: false
 packages:
 - '.'
 extra-deps:

stack-windows.yaml

@@ -11,6 +11,7 @@ flags:
     dbus: false
     debuglocks: false
     benchmark: false
+    networkbsd: false
 packages:
 - '.'
 extra-deps:

stack.yaml

@@ -11,6 +11,7 @@ flags:
     dbus: false
     debuglocks: false
     benchmark: false
+    networkbsd: false
 packages:
 - '.'
 extra-deps: