tests: check that clang uses dwarfv4 by default

tests/use-dwarf4-by-default/main.fmf

@@ -0,0 +1,20 @@
+summary: Test that clang uses DWARFv4 by default
+test: "$WITH_SCL ./test.sh"
+require:
+  - libgcc
+adjust:
+  # Common requirements when LLVM is not SCL-ized
+  - require+:
+      - clang
+      - llvm
+    when: "collection is not defined"
+
+  # Requirements for SCL-ized LLVM
+  - require+:
+      - llvm-toolset-13.0-clang
+      - llvm-toolset-13.0-llvm
+    when: "collection == llvm-toolset-13.0"
+  - require+:
+      - llvm-toolset-14.0-clang
+      - llvm-toolset-14.0-llvm
+    when: "collection == llvm-toolset-14.0"

tests/use-dwarf4-by-default/test.sh

@@ -0,0 +1,7 @@
+#!/bin/sh -eux
+
+echo "int main(){ return 0; }" | clang -g -v -x c - 2> build.log
+# Make sure that clang is using the expected flag to use DWARF 4
+grep -q "\-dwarf-version=4" build.log
+# Inspect the binary to double check expected DWARF version
+llvm-dwarfdump a.out | grep -i version | grep 0x0004