SAS reader: Support 16MiB page sizes

Fixes #286

src/readstat_malloc.c

@@ -1,9 +1,11 @@
 #include <stdlib.h>
 
-#define MAX_MALLOC_SIZE 0xFFF000
-/* ~16 MB. Needs to be at least 0x3FF00, i.e. the default ~4MB block size used
- * in compressed SPSS (ZSAV) files. The purpose here is to prevent massive
- * allocations in the event of a malformed file or a bug in the library. */
+#define MAX_MALLOC_SIZE 0x1000000
+/* =16 MiB. Needs to be at least 0x3FF00, i.e. the default ~4MB block size used
+ * in compressed SPSS (ZSAV) files. Some SAS installations use 16MiB page sizes
+ * by default, see https://github.com/tidyverse/haven/issues/697.
+ * The purpose here is to prevent massive allocations in the event of a
+ * malformed file or a bug in the library. */
 
 void *readstat_malloc(size_t len) {
     if (len > MAX_MALLOC_SIZE || len == 0) {