Check for malloc(0) to make AIX happy

Prompted by [HEIMDAL-646] by Anton Lundin

lib/wind/idn-lookup.c

@@ -73,7 +73,9 @@ lookup(const char *name)
     size_t norm_len = u_len * 2;
     uint32_t *norm = malloc(norm_len * sizeof(uint32_t));
 
-    if (u == NULL || norm == NULL)
+    if (u == NULL && u_len != 0)
+	errx(1, "malloc failed");
+    if (norm == NULL && norm_len != 0)
 	errx(1, "malloc failed");
 
     ret = wind_utf8ucs4(name, u, &u_len);

lib/wind/normalize.c

@@ -280,6 +280,11 @@ _wind_stringprep_normalize(const uint32_t *in, size_t in_len,
     uint32_t *tmp;
     int ret;
 
+    if (in_len == 0) {
+	*out_len = 0;
+	return 0;
+    }
+
     tmp_len = in_len * 4;
     if (tmp_len < MAX_LENGTH_CANON)
 	tmp_len = MAX_LENGTH_CANON;

lib/wind/stringprep.c

@@ -58,10 +58,16 @@ wind_stringprep(const uint32_t *in, size_t in_len,
 		wind_profile_flags flags)
 {
     size_t tmp_len = in_len * 3;
-    uint32_t *tmp = malloc(tmp_len * sizeof(uint32_t));
+    uint32_t *tmp;
     int ret;
     size_t olen;
 
+    if (in_len == 0) {
+	*out_len = 0;
+	return 0;
+    }
+
+    tmp = malloc(tmp_len * sizeof(uint32_t));
     if (tmp == NULL)
 	return ENOMEM;
 

lib/wind/test-map.c

@@ -64,7 +64,7 @@ try(const struct example *c)
     int ret;
     size_t out_len = c->out_len;
     uint32_t *tmp = malloc(out_len * sizeof(uint32_t));
-    if (tmp == NULL)
+    if (tmp == NULL && out_len != 0)
 	err(1, "malloc");
     ret = _wind_stringprep_map(c->in, c->in_len, tmp, &out_len, WIND_PROFILE_NAME);
     if (ret) {

lib/wind/test-normalize.c

@@ -101,7 +101,7 @@ test(char *buf)
 
     norm_len = MAX_LENGTH_CANON;
     tmp = malloc(norm_len * sizeof(size_t));
-    if (tmp == NULL)
+    if (tmp == NULL && norm_len != 0)
 	err(1, "malloc");
     ret = _wind_stringprep_normalize(in, in_len, tmp, &norm_len);
     if (ret) {