[cpullvm] Set CC/CXX in the environment for Windows builds

qualcomm-software/docs/building.md

@@ -68,34 +68,30 @@ currently-enabled embedded variants.
 > [build scripts](/qualcomm-software/scripts) for examples on how our toolchains are built and packaged
 > on different hosts.
 
-### Linux
-The commands in the sections below assume you are in the `cpullvm-toolchain/qualcomm-software` directory.
+### Configuring and building the toolchain
 
-The toolchain can be built directly with CMake.
+The commands in the sections below assume you are in the `cpullvm-toolchain/qualcomm-software` directory.
 
 All dependencies are assumed to be present in your `PATH`.
 
+First, populate the `CC` and `CXX` environment variables to tell CMake which toolchain to use:
+
+Linux:
 ```
-# Alternatively, CMAKE_C_COMPILER/CMAKE_CXX_COMPILER may be set directly
 export CC=clang
 export CXX=clang++
-mkdir build
-cd build
-cmake .. -GNinja -DFETCHCONTENT_QUIET=OFF
-ninja llvm-toolchain
+```
+Windows:
+```
+$env:CC = 'clang-cl'
+$env:CXX = 'clang-cl'
 ```
 
-### Windows
-The commands in the sections below assume you are in the `cpullvm-toolchain/qualcomm-software` directory.
-
-The toolchain can be built directly with CMake.
-
-All dependencies are assumed to be present in your `PATH`.
-
+Then, the toolchain can be configured directly with CMake and built:
 ```
 mkdir build
 cd build
-cmake .. -GNinja -DFETCHCONTENT_QUIET=OFF -DCMAKE_C_COMPILER=clang-cl -DCMAKE_CXX_COMPILER=clang-cl
+cmake .. -GNinja -DFETCHCONTENT_QUIET=OFF
 ninja llvm-toolchain
 ```
 

qualcomm-software/scripts/build.ps1

@@ -20,15 +20,16 @@ Set-VS-Env
 $repoRoot = git -C $PSScriptRoot rev-parse --show-toplevel
 $buildDir = (Join-Path $repoRoot build)
 
+$env:CC = 'clang-cl'
+$env:CXX = 'clang-cl'
+
 mkdir $buildDir
 cd $buildDir
 
 # Omit Linux runtimes, QEMU testing on Windows builds.
 cmake ..\qualcomm-software `
   -GNinja `
   -DFETCHCONTENT_QUIET=OFF `
-  -DENABLE_QEMU_TESTING=OFF `
-  -DCMAKE_C_COMPILER=clang-cl `
-  -DCMAKE_CXX_COMPILER=clang-cl
+  -DENABLE_QEMU_TESTING=OFF
 
 ninja package-llvm-toolchain

qualcomm-software/scripts/build_copy_runtimes.ps1

@@ -21,6 +21,9 @@ Set-VS-Env
 $repoRoot = git -C $PSScriptRoot rev-parse --show-toplevel
 $buildDir = (Join-Path $repoRoot build)
 
+$env:CC = 'clang-cl'
+$env:CXX = 'clang-cl'
+
 mkdir $buildDir -Force
 cd $buildDir
 
@@ -30,8 +33,6 @@ cmake ..\qualcomm-software `
   -GNinja `
   -DFETCHCONTENT_QUIET=OFF `
   -DPREBUILT_TARGET_LIBRARIES=ON `
-  -DENABLE_LINUX_LIBRARIES=ON `
-  -DCMAKE_C_COMPILER=clang-cl `
-  -DCMAKE_CXX_COMPILER=clang-cl
+  -DENABLE_LINUX_LIBRARIES=ON
 
 ninja package-llvm-toolchain