align.m4: Add stdlib.h explicitly to make the test pass on NetBSD.

Should not be problematic, every system we support right now has a
stdlib.

m4/align.m4

@@ -13,7 +13,10 @@ AC_DEFUN([AC_UNALIGNED_64_ACCESS],
 [AC_CACHE_CHECK([whether unaligned 64-bit access works],
  ac_cv_unaligned_64_access,
  [
- AC_RUN_IFELSE([AC_LANG_PROGRAM([[struct S { int a,b,c;};]],
+ AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+                                #include <stdlib.h>
+                                struct S { int a,b,c;};
+                                ]],
                                [[struct S s = {0,0,0}; long long * p = (long long *) &s.b;
 			         void *bp = malloc (50);
  				 long long x = *p;