Updates to handle use of cmake for Windows builds.

.gitignore

diff --git a/.gitignore b/.gitignore
index 52c92df..ea7e654 100644
--- a/.gitignore
+++ b/.gitignore
@@ -77,8 +77,7 @@
 javanano/target
 
 # Windows native output.
-vsprojects/Debug
-vsprojects/Release
+cmake/build
 
 # NuGet packages: we want the repository configuration, but not the
 # packages themselves.

cmake/libprotoc.cmake

diff --git a/cmake/libprotoc.cmake b/cmake/libprotoc.cmake
index 8caa9e9..e9e88af 100644
--- a/cmake/libprotoc.cmake
+++ b/cmake/libprotoc.cmake
@@ -16,7 +16,6 @@
   ${protobuf_source_dir}/src/google/protobuf/compiler/cpp/cpp_string_field.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/csharp/csharp_enum.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/csharp/csharp_enum_field.cc
-  ${protobuf_source_dir}/src/google/protobuf/compiler/csharp/csharp_extension.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/csharp/csharp_field_base.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/csharp/csharp_generator.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/csharp/csharp_helpers.cc
@@ -28,7 +27,6 @@
   ${protobuf_source_dir}/src/google/protobuf/compiler/csharp/csharp_repeated_primitive_field.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/csharp/csharp_source_generator_base.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/csharp/csharp_umbrella_class.cc
-  ${protobuf_source_dir}/src/google/protobuf/compiler/csharp/csharp_writer.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/java/java_context.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/java/java_doc_comment.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/java/java_enum.cc

csharp/generate_protos.sh

diff --git a/csharp/generate_protos.sh b/csharp/generate_protos.sh
index d239fcb..60bc281 100755
--- a/csharp/generate_protos.sh
+++ b/csharp/generate_protos.sh
@@ -23,10 +23,10 @@
 # Windows and Unix.
 if [ -z "$PROTOC" ]; then
   # TODO(jonskeet): Use an array and a for loop instead?
-  if [ -x vsprojects/Debug/protoc.exe ]; then
-    PROTOC=vsprojects/Debug/protoc.exe
-  elif [ -x vsprojects/Release/protoc.exe ]; then
-    PROTOC=vsprojects/Release/protoc.exe
+  if [ -x cmake/build/Debug/protoc.exe ]; then
+    PROTOC=cmake/build/Debug/protoc.exe
+  elif [ -x cmake/build/Release/protoc.exe ]; then
+    PROTOC=cmake/build/Release/protoc.exe
   elif [ -x src/protoc ]; then
     PROTOC=src/protoc
   else