add Windows x64 (WIN64) mode and make buildable on MSVC
diff --git a/vsprojects/grpc.sln b/vsprojects/grpc.sln
index 1f286f5..ab47b2c 100644
--- a/vsprojects/grpc.sln
+++ b/vsprojects/grpc.sln
@@ -1,7 +1,6 @@
-
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 2013
-VisualStudioVersion = 12.0.21005.1
+VisualStudioVersion = 12.0.30723.0
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "gpr", "gpr\gpr.vcxproj", "{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}"
 EndProject
@@ -49,41 +48,75 @@
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Win32 = Debug|Win32
+		Debug|x64 = Debug|x64
 		Release|Win32 = Release|Win32
+		Release|x64 = Release|x64
 	EndGlobalSection
 	GlobalSection(ProjectConfigurationPlatforms) = postSolution
 		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}.Debug|Win32.ActiveCfg = Debug|Win32
 		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}.Debug|Win32.Build.0 = Debug|Win32
+		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}.Debug|x64.ActiveCfg = Debug|x64
+		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}.Debug|x64.Build.0 = Debug|x64
 		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}.Release|Win32.ActiveCfg = Release|Win32
 		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}.Release|Win32.Build.0 = Release|Win32
+		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}.Release|x64.ActiveCfg = Release|x64
+		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}.Release|x64.Build.0 = Release|x64
 		{EAB0A629-17A9-44DB-B5FF-E91A721FE037}.Debug|Win32.ActiveCfg = Debug|Win32
 		{EAB0A629-17A9-44DB-B5FF-E91A721FE037}.Debug|Win32.Build.0 = Debug|Win32
+		{EAB0A629-17A9-44DB-B5FF-E91A721FE037}.Debug|x64.ActiveCfg = Debug|x64
+		{EAB0A629-17A9-44DB-B5FF-E91A721FE037}.Debug|x64.Build.0 = Debug|x64
 		{EAB0A629-17A9-44DB-B5FF-E91A721FE037}.Release|Win32.ActiveCfg = Release|Win32
 		{EAB0A629-17A9-44DB-B5FF-E91A721FE037}.Release|Win32.Build.0 = Release|Win32
+		{EAB0A629-17A9-44DB-B5FF-E91A721FE037}.Release|x64.ActiveCfg = Release|x64
+		{EAB0A629-17A9-44DB-B5FF-E91A721FE037}.Release|x64.Build.0 = Release|x64
 		{29D16885-7228-4C31-81ED-5F9187C7F2A9}.Debug|Win32.ActiveCfg = Debug|Win32
 		{29D16885-7228-4C31-81ED-5F9187C7F2A9}.Debug|Win32.Build.0 = Debug|Win32
+		{29D16885-7228-4C31-81ED-5F9187C7F2A9}.Debug|x64.ActiveCfg = Debug|x64
+		{29D16885-7228-4C31-81ED-5F9187C7F2A9}.Debug|x64.Build.0 = Debug|x64
 		{29D16885-7228-4C31-81ED-5F9187C7F2A9}.Release|Win32.ActiveCfg = Release|Win32
 		{29D16885-7228-4C31-81ED-5F9187C7F2A9}.Release|Win32.Build.0 = Release|Win32
+		{29D16885-7228-4C31-81ED-5F9187C7F2A9}.Release|x64.ActiveCfg = Release|x64
+		{29D16885-7228-4C31-81ED-5F9187C7F2A9}.Release|x64.Build.0 = Release|x64
 		{17BCAFC0-5FDC-4C94-AEB9-95F3E220614B}.Debug|Win32.ActiveCfg = Debug|Win32
 		{17BCAFC0-5FDC-4C94-AEB9-95F3E220614B}.Debug|Win32.Build.0 = Debug|Win32
+		{17BCAFC0-5FDC-4C94-AEB9-95F3E220614B}.Debug|x64.ActiveCfg = Debug|x64
+		{17BCAFC0-5FDC-4C94-AEB9-95F3E220614B}.Debug|x64.Build.0 = Debug|x64
 		{17BCAFC0-5FDC-4C94-AEB9-95F3E220614B}.Release|Win32.ActiveCfg = Release|Win32
 		{17BCAFC0-5FDC-4C94-AEB9-95F3E220614B}.Release|Win32.Build.0 = Release|Win32
+		{17BCAFC0-5FDC-4C94-AEB9-95F3E220614B}.Release|x64.ActiveCfg = Release|x64
+		{17BCAFC0-5FDC-4C94-AEB9-95F3E220614B}.Release|x64.Build.0 = Release|x64
 		{0A7E7F92-FDEA-40F1-A9EC-3BA484F98BBF}.Debug|Win32.ActiveCfg = Debug|Win32
 		{0A7E7F92-FDEA-40F1-A9EC-3BA484F98BBF}.Debug|Win32.Build.0 = Debug|Win32
+		{0A7E7F92-FDEA-40F1-A9EC-3BA484F98BBF}.Debug|x64.ActiveCfg = Debug|x64
+		{0A7E7F92-FDEA-40F1-A9EC-3BA484F98BBF}.Debug|x64.Build.0 = Debug|x64
 		{0A7E7F92-FDEA-40F1-A9EC-3BA484F98BBF}.Release|Win32.ActiveCfg = Release|Win32
 		{0A7E7F92-FDEA-40F1-A9EC-3BA484F98BBF}.Release|Win32.Build.0 = Release|Win32
+		{0A7E7F92-FDEA-40F1-A9EC-3BA484F98BBF}.Release|x64.ActiveCfg = Release|x64
+		{0A7E7F92-FDEA-40F1-A9EC-3BA484F98BBF}.Release|x64.Build.0 = Release|x64
 		{46CEDFFF-9692-456A-AA24-38B5D6BCF4C5}.Debug|Win32.ActiveCfg = Debug|Win32
 		{46CEDFFF-9692-456A-AA24-38B5D6BCF4C5}.Debug|Win32.Build.0 = Debug|Win32
+		{46CEDFFF-9692-456A-AA24-38B5D6BCF4C5}.Debug|x64.ActiveCfg = Debug|x64
+		{46CEDFFF-9692-456A-AA24-38B5D6BCF4C5}.Debug|x64.Build.0 = Debug|x64
 		{46CEDFFF-9692-456A-AA24-38B5D6BCF4C5}.Release|Win32.ActiveCfg = Release|Win32
 		{46CEDFFF-9692-456A-AA24-38B5D6BCF4C5}.Release|Win32.Build.0 = Release|Win32
+		{46CEDFFF-9692-456A-AA24-38B5D6BCF4C5}.Release|x64.ActiveCfg = Release|x64
+		{46CEDFFF-9692-456A-AA24-38B5D6BCF4C5}.Release|x64.Build.0 = Release|x64
 		{C187A093-A0FE-489D-A40A-6E33DE0F9FEB}.Debug|Win32.ActiveCfg = Debug|Win32
 		{C187A093-A0FE-489D-A40A-6E33DE0F9FEB}.Debug|Win32.Build.0 = Debug|Win32
+		{C187A093-A0FE-489D-A40A-6E33DE0F9FEB}.Debug|x64.ActiveCfg = Debug|x64
+		{C187A093-A0FE-489D-A40A-6E33DE0F9FEB}.Debug|x64.Build.0 = Debug|x64
 		{C187A093-A0FE-489D-A40A-6E33DE0F9FEB}.Release|Win32.ActiveCfg = Release|Win32
 		{C187A093-A0FE-489D-A40A-6E33DE0F9FEB}.Release|Win32.Build.0 = Release|Win32
+		{C187A093-A0FE-489D-A40A-6E33DE0F9FEB}.Release|x64.ActiveCfg = Release|x64
+		{C187A093-A0FE-489D-A40A-6E33DE0F9FEB}.Release|x64.Build.0 = Release|x64
 		{D64C6D63-4458-4A88-AB38-35678384A7E4}.Debug|Win32.ActiveCfg = Debug|Win32
 		{D64C6D63-4458-4A88-AB38-35678384A7E4}.Debug|Win32.Build.0 = Debug|Win32
+		{D64C6D63-4458-4A88-AB38-35678384A7E4}.Debug|x64.ActiveCfg = Debug|x64
+		{D64C6D63-4458-4A88-AB38-35678384A7E4}.Debug|x64.Build.0 = Debug|x64
 		{D64C6D63-4458-4A88-AB38-35678384A7E4}.Release|Win32.ActiveCfg = Release|Win32
 		{D64C6D63-4458-4A88-AB38-35678384A7E4}.Release|Win32.Build.0 = Release|Win32
+		{D64C6D63-4458-4A88-AB38-35678384A7E4}.Release|x64.ActiveCfg = Release|x64
+		{D64C6D63-4458-4A88-AB38-35678384A7E4}.Release|x64.Build.0 = Release|x64
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE