Index: third_party/dawn/src/dawn/common/Platform.h
--- third_party/dawn/src/dawn/common/Platform.h.orig
+++ third_party/dawn/src/dawn/common/Platform.h
@@ -60,6 +60,11 @@
 #error "Unsupported Windows platform."
 #endif
 
+#elif defined(__OpenBSD__) || defined(__FreeBSD__)
+#define DAWN_PLATFORM_IS_LINUX 1
+#define DAWN_PLATFORM_IS_BSD 1
+#define DAWN_PLATFORM_IS_POSIX 1
+
 #elif defined(__linux__)
 #define DAWN_PLATFORM_IS_LINUX 1
 #define DAWN_PLATFORM_IS_POSIX 1
