Index: lib/libc/stdio/findfp.c
===================================================================
--- lib/libc/stdio/findfp.c
+++ lib/libc/stdio/findfp.c
@@ -41,6 +41,7 @@
 #include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdint.h>
 #include <string.h>
 
 #include <spinlock.h>
@@ -96,11 +97,22 @@
 	struct glue *g;
 	static FILE empty = { ._fl_mutex = PTHREAD_MUTEX_INITIALIZER };
 	FILE *p;
+	size_t align;
 
-	g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE));
+	/*
+	 * FILE has a mbstate_t variable. This variable tries to be int64_t
+	 * aligned through its definition. int64_t may be larger than void *,
+	 * which is the size traditionally used for ALIGNBYTES.  So, use our own
+	 * rounding instead of the MI ALIGN macros. If for some reason
+	 * ALIGNBYTES is larger than int64_t, respect that too. There appears to
+	 * be no portable way to ask for FILE's alignment requirements other
+	 * than just knowing here.
+	 */
+	align = MAX(ALIGNBYTES, sizeof(int64_t));
+	g = (struct glue *)malloc(sizeof(*g) + align + n * sizeof(FILE));
 	if (g == NULL)
 		return (NULL);
-	p = (FILE *)ALIGN(g + 1);
+	p = (FILE *)roundup((uintptr_t)(g + 1), align);
 	g->next = NULL;
 	g->niobs = n;
 	g->iobs = p;