diff --git a/headers/private/kernel/arch/x86/arch_kernel.h b/headers/private/kernel/arch/x86/arch_kernel.h
index 2d250d593c..3dee56cb22 100644
--- a/headers/private/kernel/arch/x86/arch_kernel.h
+++ b/headers/private/kernel/arch/x86/arch_kernel.h
@@ -22,7 +22,7 @@
 #define KERNEL_LOAD_BASE_32_BIT			0x80000000
 #define KERNEL_LOAD_BASE_64_BIT		0xffffffff80000000ll
 #define KERNEL_FIXUP_FOR_LONG_MODE	(KERNEL_LOAD_BASE_64_BIT - KERNEL_LOAD_BASE_32_BIT)
-#elif __x86_64__
+#elif defined(__x86_64__)
 #define KERNEL_LOAD_BASE	0xffffffff80000000ll
 #else
 #define KERNEL_LOAD_BASE		0x80000000