For Travis CI - attempt to download missing D3D header from Launchpad.

Rakefile

@@ -274,6 +274,11 @@ end
 
 def makefile_ci
   if ENV['WINDOWS']
+    # MinGW package on Ubuntu 12.04 LTS does not come with d3dcompiler.h file which is required by our CI build with URHO3D_OPENGL=0.
+    # Temporarily workaround the problem by downloading the missing header from Ubuntu 14.04 LTS source package.
+    if ENV['CI'] then
+      system "sudo wget -P $(echo |$MINGW_PREFIX-gcc -v -E - 2>&1 |grep -B 1 'End of search list' |head -1) http://bazaar.launchpad.net/~ubuntu-branches/ubuntu/trusty/mingw-w64/trusty/download/package-import%40ubuntu.com-20130624192537-vzn12bb7qd5w3iy8/d3dcompiler.h-20120402093420-bk10a737hzitlkgj-65/d3dcompiler.h" or abort 'Failed to download d3dcompiler.h header'
+    end
     # LuaJIT on MinGW build is not possible on Ubuntu 12.04 LTS as its GCC cross-compiler version is too old. Fallback to use Lua library instead.
     jit = ''
     amalg = ''