diff --git a/config_host.mk.in b/config_host.mk.in
index 31590d50ea1d..3f52596779bc 100644
--- a/config_host.mk.in
+++ b/config_host.mk.in
@@ -336,6 +336,7 @@ export HAVE_CLANG_DEBUG_INFO_KIND_CONSTRUCTOR=@HAVE_CLANG_DEBUG_INFO_KIND_CONSTR
 export HAVE_CXX20_ATOMIC_REF=@HAVE_CXX20_ATOMIC_REF@
 export HAVE_DLLEXPORTINLINES=@HAVE_DLLEXPORTINLINES@
 export HAVE_EXTERNAL_DWARF=@HAVE_EXTERNAL_DWARF@
+export HAVE_LINK_DEBUG_FASTLINK=@HAVE_LINK_DEBUG_FASTLINK@
 export HAVE_LO_CLANG_DLLEXPORTINLINES=@HAVE_LO_CLANG_DLLEXPORTINLINES@
 export HAVE_GCC_AVX=@HAVE_GCC_AVX@
 export HAVE_GCC_BUILTIN_ATOMIC=@HAVE_GCC_BUILTIN_ATOMIC@
diff --git a/configure.ac b/configure.ac
index 0a7a3b858525..ad31249528eb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -5215,6 +5215,33 @@ fi
 AC_SUBST(USE_LD)
 AC_SUBST(LD)
 
+dnl ===================================================================
+dnl Check whether the linker supports -debug:fastlink, which links debug
+dnl builds faster. MSVC link.exe does; lld-link currently does not and would
+dnl warn on every link, falling back to -debug:full. Probe the selected linker
+dnl rather than hardcoding "lld has no fastlink", so a future lld-link that
+dnl gains support starts using it automatically.
+dnl ===================================================================
+HAVE_LINK_DEBUG_FASTLINK=
+if test "$_os" = "WINNT"; then
+    AC_MSG_CHECKING([whether the linker supports -debug:fastlink])
+    if test -z "$LLD_LINK"; then
+        dnl MSVC link.exe supports it natively
+        HAVE_LINK_DEBUG_FASTLINK=TRUE
+    elif "$LLD_LINK" -debug:fastlink conftest-nonexistent.obj 2>&1 | grep -iq "debug:fastlink.*debug:full"; then
+        dnl the fallback warning means fastlink is not supported
+        HAVE_LINK_DEBUG_FASTLINK=
+    else
+        HAVE_LINK_DEBUG_FASTLINK=TRUE
+    fi
+    if test -n "$HAVE_LINK_DEBUG_FASTLINK"; then
+        AC_MSG_RESULT([yes])
+    else
+        AC_MSG_RESULT([no])
+    fi
+fi
+AC_SUBST(HAVE_LINK_DEBUG_FASTLINK)
+
 HAVE_LD_BSYMBOLIC_FUNCTIONS=
 if test "$GCC" = "yes" -a "$_os" != Emscripten ; then
     AC_MSG_CHECKING([for -Bsymbolic-functions linker support])
diff --git a/solenv/gbuild/platform/com_MSC_class.mk b/solenv/gbuild/platform/com_MSC_class.mk
index 6e3a6da1a578..212a682ee86f 100644
--- a/solenv/gbuild/platform/com_MSC_class.mk
+++ b/solenv/gbuild/platform/com_MSC_class.mk
@@ -335,7 +335,7 @@ gb_Windows_PE_TARGETTYPEFLAGS := \
 ifeq ($(ENABLE_DBGUTIL),TRUE)
 # fastlink is faster but pdb files reference .obj files
 # but don't do that for setup_native DLLs: this produces make error 139 in some configurations
-gb_Windows_PE_TARGETTYPEFLAGS_DEBUGINFO = $(if $(filter -U_DLL,$(1)),-debug,-debug:fastlink)
+gb_Windows_PE_TARGETTYPEFLAGS_DEBUGINFO = $(if $(filter -U_DLL,$(1)),-debug,-debug$(if $(HAVE_LINK_DEBUG_FASTLINK),:fastlink))
 else
 gb_Windows_PE_TARGETTYPEFLAGS_DEBUGINFO = -debug
 endif