diff --git a/lib/runtime-c-api/wasmer.h b/lib/runtime-c-api/wasmer.h
index 5bb86b422..cb69a2c68 100644
--- a/lib/runtime-c-api/wasmer.h
+++ b/lib/runtime-c-api/wasmer.h
@@ -1,17 +1,20 @@
 
 #if !defined(WASMER_H_MACROS)
+
 #define WASMER_H_MACROS
 
-#if defined(MSVC)
-#if defined(_M_AMD64)
-#define ARCH_X86_64
-#endif
+// Define the `ARCH_X86_X64` constant.
+#if defined(MSVC) && defined(_M_AMD64)
+#  define ARCH_X86_64
+#elif (defined(GCC) || defined(__GNUC__) || defined(__clang__)) && defined(__x86_64__)
+#  define ARCH_X86_64
 #endif
 
+// Define the `DEPRECATED` macro.
 #if defined(GCC) || defined(__GNUC__) || defined(__clang__)
-#if defined(__x86_64__)
-#define ARCH_X86_64
-#endif
+#  define DEPRECATED(message) __attribute__((deprecated(message)))
+#elif defined(MSVC)
+#  define DEPRECATED(message) __declspec(deprecated(message))
 #endif
 
 #define WASMER_WASI_ENABLED
diff --git a/lib/runtime-c-api/wasmer.hh b/lib/runtime-c-api/wasmer.hh
index fe0fcd7f5..00b3c287a 100644
--- a/lib/runtime-c-api/wasmer.hh
+++ b/lib/runtime-c-api/wasmer.hh
@@ -1,17 +1,20 @@
 
 #if !defined(WASMER_H_MACROS)
+
 #define WASMER_H_MACROS
 
-#if defined(MSVC)
-#if defined(_M_AMD64)
-#define ARCH_X86_64
-#endif
+// Define the `ARCH_X86_X64` constant.
+#if defined(MSVC) && defined(_M_AMD64)
+#  define ARCH_X86_64
+#elif (defined(GCC) || defined(__GNUC__) || defined(__clang__)) && defined(__x86_64__)
+#  define ARCH_X86_64
 #endif
 
+// Define the `DEPRECATED` macro.
 #if defined(GCC) || defined(__GNUC__) || defined(__clang__)
-#if defined(__x86_64__)
-#define ARCH_X86_64
-#endif
+#  define DEPRECATED(message) __attribute__((deprecated(message)))
+#elif defined(MSVC)
+#  define DEPRECATED(message) __declspec(deprecated(message))
 #endif
 
 #define WASMER_WASI_ENABLED