[System.Net.Http] Add a way to add extra build arguments.

This is used by monotouch to add a reference to monotouch.dll.

Also add a profile-specific sources file for monotouch so the
extensions module can add even more files.

mcs/class/System.Net.Http/Makefile

@@ -4,7 +4,7 @@ include ../../build/rules.make
 
 LIBRARY = System.Net.Http.dll
 
-LIB_MCS_FLAGS = -r:System.Core.dll -r:System.dll
+LIB_MCS_FLAGS = -r:System.Core.dll -r:System.dll $(EXTRA_LIB_MCS_FLAGS)
 
 TEST_MCS_FLAGS = -r:System.dll -r:System.Core.dll
 

mcs/class/System.Net.Http/monotouch_System.Net.Http.dll.sources

@@ -0,0 +1,53 @@
+../../build/common/Consts.cs
+Assembly/AssemblyInfo.cs
+System.Net.Http/ByteArrayContent.cs
+System.Net.Http/ClientCertificateOption.cs
+System.Net.Http/DelegatingHandler.cs
+System.Net.Http/FormUrlEncodedContent.cs
+System.Net.Http/HttpClient.cs
+System.Net.Http/HttpClientHandler.cs
+System.Net.Http/HttpCompletionOption.cs
+System.Net.Http/HttpContent.cs
+System.Net.Http/HttpMessageHandler.cs
+System.Net.Http/HttpMessageInvoker.cs
+System.Net.Http/HttpMethod.cs
+System.Net.Http/HttpRequestException.cs
+System.Net.Http/HttpRequestMessage.cs
+System.Net.Http/HttpResponseMessage.cs
+System.Net.Http/MessageProcessingHandler.cs
+System.Net.Http/MultipartContent.cs
+System.Net.Http/MultipartFormDataContent.cs
+System.Net.Http/StreamContent.cs
+System.Net.Http/StringContent.cs
+System.Net.Http.Headers/AuthenticationHeaderValue.cs
+System.Net.Http.Headers/CacheControlHeaderValue.cs
+System.Net.Http.Headers/CollectionExtensions.cs
+System.Net.Http.Headers/ContentDispositionHeaderValue.cs
+System.Net.Http.Headers/ContentRangeHeaderValue.cs
+System.Net.Http.Headers/EntityTagHeaderValue.cs
+System.Net.Http.Headers/HashCodeCalculator.cs
+System.Net.Http.Headers/HeaderInfo.cs
+System.Net.Http.Headers/HttpContentHeaders.cs
+System.Net.Http.Headers/HttpHeaderKind.cs
+System.Net.Http.Headers/HttpHeaders.cs
+System.Net.Http.Headers/HttpHeaderValueCollection.cs
+System.Net.Http.Headers/HttpRequestHeaders.cs
+System.Net.Http.Headers/HttpResponseHeaders.cs
+System.Net.Http.Headers/Lexer.cs
+System.Net.Http.Headers/MediaTypeHeaderValue.cs
+System.Net.Http.Headers/MediaTypeWithQualityHeaderValue.cs
+System.Net.Http.Headers/NameValueHeaderValue.cs
+System.Net.Http.Headers/NameValueWithParametersHeaderValue.cs
+System.Net.Http.Headers/Parser.cs
+System.Net.Http.Headers/ProductHeaderValue.cs
+System.Net.Http.Headers/ProductInfoHeaderValue.cs
+System.Net.Http.Headers/QualityValue.cs
+System.Net.Http.Headers/RangeConditionHeaderValue.cs
+System.Net.Http.Headers/RangeHeaderValue.cs
+System.Net.Http.Headers/RangeItemHeaderValue.cs
+System.Net.Http.Headers/RetryConditionHeaderValue.cs
+System.Net.Http.Headers/StringWithQualityHeaderValue.cs
+System.Net.Http.Headers/TransferCodingHeaderValue.cs
+System.Net.Http.Headers/TransferCodingWithQualityHeaderValue.cs
+System.Net.Http.Headers/ViaHeaderValue.cs
+System.Net.Http.Headers/WarningHeaderValue.cs