Merge 5ae4721b7e1b690e42b01227e22b76e33a3b2348 into 758d39eb239e6554d3ac0659b6f592fcd5317c24

.github/workflows/linux.yml

@@ -179,6 +179,13 @@ jobs:
         sudo apt install locales-all
         cmake -E make_directory ${{runner.workspace}}/build
 
+    - name: Select matching C compiler
+      run: |
+        cc=${{matrix.cxx}}
+        cc=${cc/clang++/clang}
+        cc=${cc/g++/gcc}
+        echo "CC=$cc" >> "$GITHUB_ENV"
+
     - name: Configure
       working-directory: ${{runner.workspace}}/build
       env:

test/CMakeLists.txt

@@ -242,6 +242,14 @@ if (FMT_CUDA_TEST)
 endif ()
 
 enable_language(C)
-add_executable(c-test c-test.c)
-target_link_libraries(c-test PRIVATE fmt::fmt-c)
-add_test(NAME c-test COMMAND c-test)
+# Clang < 3.8 doesn't apply array-to-pointer decay to the controlling
+# expression of _Generic (https://llvm.org/PR16340), so fmt-c.h's argument
+# dispatch doesn't match string literals there.
+if (CMAKE_C_COMPILER_ID STREQUAL "Clang" AND CMAKE_C_COMPILER_VERSION
+                                             VERSION_LESS 3.8)
+  message(STATUS "Skipping c-test: _Generic is broken in Clang < 3.8")
+else ()
+  add_executable(c-test c-test.c)
+  target_link_libraries(c-test PRIVATE fmt::fmt-c)
+  add_test(NAME c-test COMMAND c-test)
+endif ()