[llvm] [llvm] Fix cmake string expansion in CrossCompile.cmake (PR #138901)

[David Truby via llvm-commits]

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@@ -83,9 +83,9 @@ function(llvm_create_cross_target project_name target_name toolchain buildtype)
 
   add_custom_command(OUTPUT ${${project_name}_${target_name}_BUILD}/CMakeCache.txt
     COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}"
-        -DCMAKE_MAKE_PROGRAM="${CMAKE_MAKE_PROGRAM}"
-        -DCMAKE_C_COMPILER_LAUNCHER="${CMAKE_C_COMPILER_LAUNCHER}"
-        -DCMAKE_CXX_COMPILER_LAUNCHER="${CMAKE_CXX_COMPILER_LAUNCHER}"
+        "-DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM}"
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DavidTruby wrote:

I didn't have one specifically for the CMAKE_MAKE_PROGRAM, I just thought I'd fx it as well while I was here as the same reasoning would apply there.
We want this for CMAKE_C_COMPILER_LAUNCHER, where we want to add flags to `ccache` when using LLVM_CCACHE_BUILD to control certain behaviour especially when building flang. When we tried to make that change it worked on non-Windows but didn't work on Windows, this fixes at least that case. So that's the specific motivation for the change.

https://github.com/llvm/llvm-project/pull/138901