[llvm] 07022e6 - [docs] Note about how to handle 'llvm-mt: error: no libxml2'

[Hans Wennborg via llvm-commits]

Author: Hans Wennborg
Date: 2022-07-15T16:03:07+02:00
New Revision: 07022e6cf9b5b3baa642be53d0b3c3f1c403dbfd

URL: https://github.com/llvm/llvm-project/commit/07022e6cf9b5b3baa642be53d0b3c3f1c403dbfd
DIFF: https://github.com/llvm/llvm-project/commit/07022e6cf9b5b3baa642be53d0b3c3f1c403dbfd.diff

LOG: [docs] Note about how to handle 'llvm-mt: error: no libxml2'

See https://github.com/llvm/llvm-project/issues/55817 and
https://discourse.llvm.org/t/cannot-cmake-self-hosted-clang-on-windows-for-lack-of-libxml2/58793

Not sure where is the best place to put this, but hopefully this will be
found by those searching for the error message.

Differential revision: https://reviews.llvm.org/D129770

Added: 
    

Modified: 
    llvm/docs/CMake.rst

Removed: 
    


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diff  --git a/llvm/docs/CMake.rst b/llvm/docs/CMake.rst
index 10945618e2f94..d16bf78df8d50 100644
--- a/llvm/docs/CMake.rst
+++ b/llvm/docs/CMake.rst
@@ -1066,10 +1066,25 @@ Compiler/Platform-specific topics
 
 Notes for specific compilers and/or platforms.
 
-Microsoft Visual C++
---------------------
+Windows
+-------
 
 **LLVM_COMPILER_JOBS**:STRING
   Specifies the maximum number of parallel compiler jobs to use per project
   when building with msbuild or Visual Studio. Only supported for the Visual
   Studio 2010 CMake generator. 0 means use all processors. Default is 0.
+
+**CMAKE_MT**:STRING
+  When compiling with clang-cl, recent CMake versions will default to selecting
+  `llvm-mt` as the Manifest Tool instead of Microsoft's `mt.exe`. This will
+  often cause errors like:
+
+  .. code-block:: console
+
+    -- Check for working C compiler: [...]clang-cl.exe - broken
+    [...]
+        MT: command [...] failed (exit code 0x1) with the following output:
+        llvm-mt: error: no libxml2
+        ninja: build stopped: subcommand failed.
+
+  To work around this error, set `CMAKE_MT=mt`.