diff --git a/double-conversion/double-conversion.cc b/double-conversion/double-conversion.cc
index 4c5d995..388cb39 100644
--- a/double-conversion/double-conversion.cc
+++ b/double-conversion/double-conversion.cc
@@ -529,7 +529,7 @@
 // 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.
-#if _MSC_VER
+#ifdef _MSC_VER
 #pragma optimize("",off)
 static bool IsDecimalDigitForRadix(int c, int radix) {
   return '0' <= c && c <= '9' && (c - '0') < radix;
diff --git a/double-conversion/utils.h b/double-conversion/utils.h
index 2e1be0d..47489f6 100644
--- a/double-conversion/utils.h
+++ b/double-conversion/utils.h
@@ -94,7 +94,8 @@
     defined(_MIPS_ARCH_MIPS32R2) || \
     defined(__AARCH64EL__) || defined(__aarch64__) || defined(__AARCH64EB__) || \
     defined(__riscv) || \
-    defined(__or1k__) || defined(__arc__)
+    defined(__or1k__) || defined(__arc__) || \
+    defined(__EMSCRIPTEN__)
 #define DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS 1
 #elif defined(__mc68000__) || \
     defined(__pnacl__) || defined(__native_client__)