--- a/config/config.mk
+++ b/config/config.mk
@@ -265,17 +265,17 @@ OS_LDFLAGS += $(MOZ_MEMORY_LDFLAGS)
 endif
 
 # MOZ_DEBUG_SYMBOLS generates debug symbols in separate PDB files.
 # Used for generating an optimized build with debugging symbols.
 # Used in the Windows nightlies to generate symbols for crash reporting.
 ifdef MOZ_DEBUG_SYMBOLS
 OS_CXXFLAGS += -Zi -UDEBUG -DNDEBUG
 OS_CFLAGS += -Zi -UDEBUG -DNDEBUG
-OS_LDFLAGS += -DEBUG -OPT:REF -OPT:nowin98
+OS_LDFLAGS += -DEBUG -OPT:REF
 endif
 
 ifdef MOZ_QUANTIFY
 # -FIXED:NO is needed for Quantify to work, but it increases the size
 # of executables, so only use it if building for Quantify.
 WIN32_EXE_LDFLAGS += -FIXED:NO
 
 # We need -OPT:NOICF to prevent identical methods from being merged together.

--- a/configure.in
+++ b/configure.in
@@ -626,16 +626,23 @@ case "$target" in
             AC_DEFINE(_CRT_NONSTDC_NO_DEPRECATE)
         elif test "$_CC_MAJOR_VERSION" = "15"; then
             _CC_SUITE=9
             CXXFLAGS="$CXXFLAGS -Zc:wchar_t-"
             LDFLAGS="$LDFLAGS -MANIFESTUAC:NO"
             _USE_DYNAMICBASE=1
             AC_DEFINE(_CRT_SECURE_NO_WARNINGS)
             AC_DEFINE(_CRT_NONSTDC_NO_WARNINGS)
+        elif test "$_CC_MAJOR_VERSION" = "16"; then
+            _CC_SUITE=10
+            CXXFLAGS="$CXXFLAGS -Zc:wchar_t-"
+            LDFLAGS="$LDFLAGS -MANIFESTUAC:NO"
+            _USE_DYNAMICBASE=1
+            AC_DEFINE(_CRT_SECURE_NO_WARNINGS)
+            AC_DEFINE(_CRT_NONSTDC_NO_WARNINGS)
         else
             AC_MSG_ERROR([This version of the MSVC compiler, $CC_VERSION , is unsupported.])
         fi
 
         _MOZ_RTTI_FLAGS_ON='-GR'
         _MOZ_RTTI_FLAGS_OFF='-GR-'
         _MOZ_EXCEPTIONS_FLAGS_ON='-EHsc'
         _MOZ_EXCEPTIONS_FLAGS_OFF=''