wrappers: Force the default dwarf version back to 4

Clang's general default dwarf version was raised from 4 to 5 in
d3b26dea16108c427b19b5480c9edc76edf8f5b4 in llvm-project (Jan 23
2022) before the 14.0.0 branch, but dwarf 5 on Windows seems to not
work with either LLDB or GDB.

Thus force the default back to 4 here as a temporary workaround, and try
to set the default back to 4 for mingw targets in Clang for later
releases (https://reviews.llvm.org/D119326).

Author: mstorsjo

wrappers/clang-target-wrapper.c

@@ -95,6 +95,7 @@ int _tmain(int argc, TCHAR* argv[]) {
     exec_argv[arg++] = _T("-unwindlib=libunwind");
     exec_argv[arg++] = _T("-stdlib=libc++");
     exec_argv[arg++] = _T("-fuse-ld=lld");
+    exec_argv[arg++] = _T("-fdebug-default-version=4");
     exec_argv[arg++] = _T("--end-no-unused-arguments");
 
     for (int i = 1; i < argc; i++)

wrappers/clang-target-wrapper.sh

@@ -88,6 +88,7 @@ FLAGS="$FLAGS -rtlib=compiler-rt"
 FLAGS="$FLAGS -unwindlib=libunwind"
 FLAGS="$FLAGS -stdlib=libc++"
 FLAGS="$FLAGS -fuse-ld=lld"
+FLAGS="$FLAGS -fdebug-default-version=4"
 FLAGS="$FLAGS --end-no-unused-arguments"
 
 $CCACHE "$CLANG" $FLAGS "$@"