diff --git a/double-conversion/string-to-double.cc b/double-conversion/string-to-double.cc
index 12b88f9..03ad670 100644
--- a/double-conversion/string-to-double.cc
+++ b/double-conversion/string-to-double.cc
@@ -35,6 +35,18 @@
 #include "strtod.h"
 #include "utils.h"
 
+#ifdef _MSC_VER
+#  if _MSC_VER >= 1900
+// Fix MSVC >= 2015 (_MSC_VER == 1900) warning
+// C4244: 'argument': conversion from 'const uc16' to 'char', possible loss of data
+// against Advance and friends, when instantiated with **it as char, not uc16.
+ __pragma(warning(disable: 4244))
+#  endif
+#  if _MSC_VER <= 1700 // VS2012, see IsDecimalDigitForRadix warning fix, below
+#    define VS2012_RADIXWARN
+#  endif
+#endif
+
 namespace double_conversion {
 
 namespace {
@@ -149,9 +161,9 @@
 //
 // The function is small and could be inlined, but VS2012 emitted a warning
 // because it constant-propagated the radix and concluded that the last
-// condition was always true. By moving it into a separate function the
-// compiler wouldn't warn anymore.
-#ifdef _MSC_VER
+// condition was always true. Moving it into a separate function and
+// suppressing optimisation keeps the compiler from warning.
+#ifdef VS2012_RADIXWARN
 #pragma optimize("",off)
 static bool IsDecimalDigitForRadix(int c, int radix) {
   return '0' <= c && c <= '9' && (c - '0') < radix;
diff --git a/double-conversion/strtod.cc b/double-conversion/strtod.cc
index 441be76..850bcda 100644
--- a/double-conversion/strtod.cc
+++ b/double-conversion/strtod.cc
@@ -202,6 +202,10 @@
                          int exponent,
                          double* result) {
 #if !defined(DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS)
+  // Avoid "unused parameter" warnings
+  (void) trimmed;
+  (void) exponent;
+  (void) result;
   // On x86 the floating-point stack can be 64 or 80 bits wide. If it is
   // 80 bits wide (as is the case on Linux) then double-rounding occurs and the
   // result is not accurate.
diff --git a/double-conversion/utils.h b/double-conversion/utils.h
index 438d055..c72c333 100644
--- a/double-conversion/utils.h
+++ b/double-conversion/utils.h
@@ -108,7 +108,7 @@
     defined(__ARMEL__) || defined(__avr32__) || defined(_M_ARM) || defined(_M_ARM64) || \
     defined(__hppa__) || defined(__ia64__) || \
     defined(__mips__) || \
-    defined(__nios2__) || \
+    defined(__nios2__) || defined(__ghs) || \
     defined(__powerpc__) || defined(__ppc__) || defined(__ppc64__) || \
     defined(_POWER) || defined(_ARCH_PPC) || defined(_ARCH_PPC64) || \
     defined(__sparc__) || defined(__sparc) || defined(__s390__) || \