Create FreeBSD build-target for corefx.

This partially adresses
https://github.com/dotnet/corefx/issues/1626

Author: josteink

dir.props

@@ -137,6 +137,7 @@
     <OSGroup Condition="'$(OSGroup)'=='' and $(Configuration.StartsWith('Windows'))">Windows_NT</OSGroup>
     <OSGroup Condition="'$(OSGroup)'=='' and $(Configuration.StartsWith('Linux'))">Linux</OSGroup>
     <OSGroup Condition="'$(OSGroup)'=='' and $(Configuration.StartsWith('OSX'))">OSX</OSGroup>
+    <OSGroup Condition="'$(OSGroup)'=='' and $(Configuration.StartsWith('FreeBSD'))">FreeBSD</OSGroup>
     <OSGroup Condition="'$(OSGroup)'==''">Windows_NT</OSGroup>
   </PropertyGroup>
 
@@ -189,8 +190,9 @@
     <TargetsWindows Condition="'$(OSGroup)' == 'Windows_NT'">true</TargetsWindows>
     <TargetsLinux Condition="'$(OSGroup)' == 'Linux'">true</TargetsLinux>
     <TargetsOSX Condition="'$(OSGroup)' == 'OSX'">true</TargetsOSX>
+    <TargetsFreeBSD Condition="'$(OSGroup)' == 'FreeBSD'">true</TargetsFreeBSD>
 
-    <TargetsUnix Condition="'$(TargetsLinux)' == 'true' or '$(TargetsOSX)' == 'true'">true</TargetsUnix>
+    <TargetsUnix Condition="'$(TargetsLinux)' == 'true' or '$(TargetsOSX)' == 'true' or '$(TargetsFreeBSD)' == 'true'">true</TargetsUnix>
   </PropertyGroup>
 
   <PropertyGroup>

src/System.Runtime.Environment/src/System.Runtime.Environment.csproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.props))\dir.props" />
   <PropertyGroup>
@@ -17,7 +17,7 @@
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'OSX_Release|AnyCPU' " />
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Windows_Debug|AnyCPU' " />
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Windows_Release|AnyCPU' " />
-  <ItemGroup Condition=" '$(TargetsWindows)' == 'true' ">
+    <ItemGroup Condition=" '$(TargetsWindows)' == 'true' ">
     <Compile Include="RuntimeInformation.Windows.cs" />
   </ItemGroup>
   <ItemGroup Condition=" '$(TargetsLinux)' == 'true' ">
@@ -33,4 +33,4 @@
     <Compile Include="OSName.cs" />
   </ItemGroup>
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
-</Project>
+</Project>