Build libclang, add it to nuget, add python bindings (llvm#149)

Context: dotnet/runtime#62485

* Build clang, add it to nuget, add python bindings

* Disable few clang options for quicker build

* Fix nuget props on OSX and linux

The clang libs are already in the lib directory

* Change build timeout, do not build clang on arm

The windows/x64 build now takes around 120 minutes so increase
the timeout to 140 minutes.

We don't build mono/wasm on arm so we don't need to build clang for arm
targets.

* Add libclang.dll to non-arm nuget's only

Author: radekdoulik

llvm.proj

@@ -64,6 +64,13 @@
   <ItemGroup>
     <_LLVMBuildArgs Condition="'$(BuildOS)' == 'Linux'" Include='-DCMAKE_SHARED_LINKER_FLAGS=-Wl,--build-id' />
   </ItemGroup>
+  <ItemGroup Condition="'$(TargetArchitecture)' != 'arm' and '$(TargetArchitecture)' != 'arm64'">
+    <_LLVMBuildArgs Include='-DLLVM_ENABLE_PROJECTS=clang' />
+    <_LLVMBuildArgs Include='-DCLANG_BUILD_TOOLS:BOOL=OFF' />
+    <_LLVMBuildArgs Include='-DCLANG_INCLUDE_TESTS:BOOL=OFF' />
+    <_LLVMBuildArgs Include='-DCLANG_ENABLE_ARCMT:BOOL=OFF' />
+    <_LLVMBuildArgs Include='-DCLANG_ENABLE_STATIC_ANALYZER:BOOL=OFF' />
+  </ItemGroup>
 
   <PropertyGroup Condition="'$(BuildOS)' != 'Windows_NT'">
     <_CrossCFlags Condition="'$(BuildOS)' == 'Linux' and '$(TargetArchitecture)' == 'arm64'">--target=aarch64-linux-gnu --sysroot=$(ROOTFS_DIR)</_CrossCFlags>

nuget/Microsoft.NETCore.Runtime.Mono.LLVM.Sdk/runtime.Linux.Microsoft.NETCore.Runtime.Mono.LLVM.Sdk.props

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project>
   <ItemGroup>
+    <File Include="$(ProjectDir)\clang\bindings\python\clang\**" TargetPath="bindings\python\clang\" />
     <File Include="$(_LLVMInstallDir)\bin\llvm-config" TargetPath="tools\$(PackageTargetRuntime)\bin\" />
     <File Include="$(_LLVMInstallDir)\bin\llvm-dis" TargetPath="tools\$(PackageTargetRuntime)\bin\" />
     <File Include="$(_LLVMInstallDir)\bin\llvm-tblgen" TargetPath="tools\$(PackageTargetRuntime)\bin\" />

nuget/Microsoft.NETCore.Runtime.Mono.LLVM.Sdk/runtime.OSX.Microsoft.NETCore.Runtime.Mono.LLVM.Sdk.props

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project>
   <ItemGroup>
+    <File Include="$(ProjectDir)\clang\bindings\python\clang\**" TargetPath="bindings\python\clang\" />
     <File Include="$(_LLVMInstallDir)\bin\llvm-config" TargetPath="tools\$(PackageTargetRuntime)\bin\" />
     <File Include="$(_LLVMInstallDir)\bin\llvm-dis" TargetPath="tools\$(PackageTargetRuntime)\bin\" />
     <File Include="$(_LLVMInstallDir)\bin\llvm-tblgen" TargetPath="tools\$(PackageTargetRuntime)\bin\" />

nuget/Microsoft.NETCore.Runtime.Mono.LLVM.Sdk/runtime.Windows_NT.Microsoft.NETCore.Runtime.Mono.LLVM.Sdk.props

@@ -1,6 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project>
   <ItemGroup>
+    <File Include="$(ProjectDir)\clang\bindings\python\clang\**" TargetPath="bindings\python\clang\" />
+    <File Include="$(_LLVMInstallDir)\bin\libclang.dll" TargetPath="tools\$(PackageTargetRuntime)\bin\" Condition="'$(TargetArchitecture)' != 'arm' and '$(TargetArchitecture)' != 'arm64'" />
     <File Include="$(_LLVMInstallDir)\bin\llvm-config.exe" TargetPath="tools\$(PackageTargetRuntime)\bin\" />
     <File Include="$(_LLVMInstallDir)\bin\llvm-dis.exe" TargetPath="tools\$(PackageTargetRuntime)\bin\" />
     <File Include="$(_LLVMInstallDir)\bin\llvm-tblgen.exe" TargetPath="tools\$(PackageTargetRuntime)\bin\" />