[PATCH 1/2] gdb/testsuite: Force lld-link linker on windows-msvc

clang windows-msvc defaults to using the Microsoft link.exe linker.
That does not work with DWARF though, we have to use lld-link instead.
That is why the whole windows-msvc support in the testsuite assumes
the linker in use is lld-link.

So far, I've been running the testsuite with
CC_FOR_TARGET/CXX_FOR_TARGET pointing at a clang wrapper script that
adds "-fuse-ld=lld-link", but I think this belongs in the testsuite
directly, since it's not really optional.

Change-Id: I5bcafa408696b349b829b4ffbd75037be25b3f3b
---
 gdb/testsuite/lib/gdb.exp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 6fb04869605..912ddf1cd54 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -6660,6 +6660,15 @@ proc gdb_compile {source dest type options} {
 	}
     }
 
+    if {[istarget "*-*-windows-msvc*"]} {
+	# Clang wants to use the Microsoft linker by default.  That
+	# doesn't support DWARF, so link with lld-link instead, which
+	# does support DWARF (and PDB/CodeView).  Pass -Xarch_host so
+	# that when we're compiling HIP code, we only affect the host
+	# linker.
+	lappend new_options "early_flags=-Xarch_host -fuse-ld=lld-link"
+    }
+
     # If the 'build-id' option is used, then ensure that we generate a
     # build-id.  It is possible that the compiler is configured to do
     # so automatically, but at least for GCC the configure option
-- 
2.54.0