diff --git a/mongoose.c b/mongoose.c
index f34eb139..16ef5a23 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -14611,7 +14611,7 @@ typedef uint16_t comp;            /**< A single precision component. */
 typedef uint32_t long_comp;       /**< A double precision component. */
 typedef int32_t slong_comp;       /**< A signed double precision component. */
 #else                        /* regular 32 bit */
-#ifdef WIN32
+#ifdef _MSC_VER
 #define COMP_RADIX 4294967296i64
 #define COMP_MAX 0xFFFFFFFFFFFFFFFFui64
 #else
diff --git a/src/tls_rsa.c b/src/tls_rsa.c
index 5543549a..b066722e 100644
--- a/src/tls_rsa.c
+++ b/src/tls_rsa.c
@@ -63,7 +63,7 @@ typedef uint16_t comp;            /**< A single precision component. */
 typedef uint32_t long_comp;       /**< A double precision component. */
 typedef int32_t slong_comp;       /**< A signed double precision component. */
 #else                        /* regular 32 bit */
-#ifdef WIN32
+#ifdef _MSC_VER
 #define COMP_RADIX 4294967296i64
 #define COMP_MAX 0xFFFFFFFFFFFFFFFFui64
 #else