<limits.h> is required for SIZE_MAX. Fixes Android build.

src/libsodium/crypto_pwhash/scryptxsalsa208sha256/nosse/pwhash_scryptxsalsa208sha256.c

@@ -29,6 +29,7 @@
  */
 
 #include <errno.h>
+#include <limits.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>

src/libsodium/crypto_pwhash/scryptxsalsa208sha256/sse/pwhash_scryptxsalsa208sha256.c

@@ -35,6 +35,7 @@
 #endif
 
 #include <errno.h>
+#include <limits.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>