WIP: github: Use a nightly compiler build

This is needed for both openmp and compiler-rt tests.

Author: mstorsjo

.github/workflows/build.yml

@@ -351,7 +351,7 @@ jobs:
             make
       - name: Unpack toolchain
         run: |
-          curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/20250417/llvm-mingw-20250417-ucrt-${{matrix.arch}}.zip
+          curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/nightly/llvm-mingw-nightly-ucrt-${{matrix.arch}}.zip
           unzip -q llvm-mingw-*.zip
           rm llvm-mingw-*.zip
           mv llvm-mingw-* /llvm-mingw
@@ -390,7 +390,7 @@ jobs:
           choco install ninja
       - name: Unpack toolchain
         run: |
-          curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/20250417/llvm-mingw-20250417-ucrt-${{matrix.arch}}.zip
+          curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/nightly/llvm-mingw-nightly-ucrt-${{matrix.arch}}.zip
           Expand-Archive llvm-mingw-*.zip -DestinationPath .
           del llvm-mingw-*.zip
           mv llvm-mingw-* c:\llvm-mingw
@@ -450,7 +450,7 @@ jobs:
           choco install ninja
       - name: Unpack toolchain
         run: |
-          curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/20250417/llvm-mingw-20250417-ucrt-${{matrix.arch}}.zip
+          curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/nightly/llvm-mingw-nightly-ucrt-${{matrix.arch}}.zip
           Expand-Archive llvm-mingw-*.zip -DestinationPath .
           del llvm-mingw-*.zip
           mv llvm-mingw-* c:\llvm-mingw
@@ -514,7 +514,7 @@ jobs:
           choco install ninja
       - name: Unpack toolchain
         run: |
-          curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/20250417/llvm-mingw-20250417-ucrt-${{matrix.arch}}.zip
+          curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/nightly/llvm-mingw-nightly-ucrt-${{matrix.arch}}.zip
           Expand-Archive llvm-mingw-*.zip -DestinationPath .
           del llvm-mingw-*.zip
           mv llvm-mingw-* c:\llvm-mingw
@@ -651,7 +651,7 @@ jobs:
             nasm:p
       - name: Unpack toolchain
         run: |
-          curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/20250417/llvm-mingw-20250417-ucrt-${{matrix.arch}}.zip
+          curl -LO https://github.com/mstorsjo/llvm-mingw/releases/download/nightly/llvm-mingw-nightly-ucrt-${{matrix.arch}}.zip
           unzip -q llvm-mingw-*.zip
           rm llvm-mingw-*.zip
           mv llvm-mingw-* /llvm-mingw