Index: include/cstddef
===================================================================
--- include/cstddef
+++ include/cstddef
@@ -50,7 +50,7 @@
 using ::size_t;
 
 #if defined(__CLANG_MAX_ALIGN_T_DEFINED) || defined(_GCC_MAX_ALIGN_T) || \
-    defined(__DEFINED_max_align_t)
+    defined(__DEFINED_max_align_t) || defined(__NetBSD__)
 // Re-use the compiler's <stddef.h> max_align_t where possible.
 using ::max_align_t;
 #else
Index: include/stddef.h
===================================================================
--- include/stddef.h
+++ include/stddef.h
@@ -54,7 +54,7 @@
 
 // Re-use the compiler's <stddef.h> max_align_t where possible.
 #if !defined(__CLANG_MAX_ALIGN_T_DEFINED) && !defined(_GCC_MAX_ALIGN_T) && \
-    !defined(__DEFINED_max_align_t)
+    !defined(__DEFINED_max_align_t) && !defined(__NetBSD__)
 typedef long double max_align_t;
 #endif