diff --git a/compat/regex/regcomp.c b/compat/regex/regcomp.c
index d1bc09e49b6675..2bc0f1187a18f2 100644
--- a/compat/regex/regcomp.c
+++ b/compat/regex/regcomp.c
@@ -868,7 +868,7 @@ init_dfa (re_dfa_t *dfa, size_t pat_len)
     if (table_size > pat_len)
       break;
 
-  dfa->state_table = calloc (sizeof (struct re_state_table_entry), table_size);
+  dfa->state_table = calloc (table_size, sizeof (struct re_state_table_entry));
   dfa->state_hash_mask = table_size - 1;
 
   dfa->mb_cur_max = MB_CUR_MAX;
@@ -936,7 +936,7 @@ init_dfa (re_dfa_t *dfa, size_t pat_len)
 	{
 	  int i, j, ch;
 
-	  dfa->sb_char = (re_bitset_ptr_t) calloc (sizeof (bitset_t), 1);
+	  dfa->sb_char = (re_bitset_ptr_t) calloc (1, sizeof (bitset_t));
 	  if (BE (dfa->sb_char == NULL, 0))
 	    return REG_ESPACE;
 
@@ -3079,9 +3079,9 @@ parse_bracket_exp (re_string_t *regexp, re_dfa_t *dfa, re_token_t *token,
 						   _NL_COLLATE_SYMB_EXTRAMB);
     }
 #endif
-  sbcset = (re_bitset_ptr_t) calloc (sizeof (bitset_t), 1);
+  sbcset = (re_bitset_ptr_t) calloc (1, sizeof (bitset_t));
 #ifdef RE_ENABLE_I18N
-  mbcset = (re_charset_t *) calloc (sizeof (re_charset_t), 1);
+  mbcset = (re_charset_t *) calloc (1, sizeof (re_charset_t));
 #endif /* RE_ENABLE_I18N */
 #ifdef RE_ENABLE_I18N
   if (BE (sbcset == NULL || mbcset == NULL, 0))
@@ -3626,9 +3626,9 @@ build_charclass_op (re_dfa_t *dfa, RE_TRANSLATE_TYPE trans,
   re_token_t br_token;
   bin_tree_t *tree;
 
-  sbcset = (re_bitset_ptr_t) calloc (sizeof (bitset_t), 1);
+  sbcset = (re_bitset_ptr_t) calloc (1, sizeof (bitset_t));
 #ifdef RE_ENABLE_I18N
-  mbcset = (re_charset_t *) calloc (sizeof (re_charset_t), 1);
+  mbcset = (re_charset_t *) calloc (1, sizeof (re_charset_t));
 #endif /* RE_ENABLE_I18N */
 
 #ifdef RE_ENABLE_I18N
diff --git a/compat/regex/regex_internal.c b/compat/regex/regex_internal.c
index ec51cf34461ef2..ec5cc5d2dd10f8 100644
--- a/compat/regex/regex_internal.c
+++ b/compat/regex/regex_internal.c
@@ -1628,7 +1628,7 @@ create_ci_newstate (const re_dfa_t *dfa, const re_node_set *nodes,
   reg_errcode_t err;
   re_dfastate_t *newstate;
 
-  newstate = (re_dfastate_t *) calloc (sizeof (re_dfastate_t), 1);
+  newstate = (re_dfastate_t *) calloc (1, sizeof (re_dfastate_t));
   if (BE (newstate == NULL, 0))
     return NULL;
   err = re_node_set_init_copy (&newstate->nodes, nodes);
@@ -1678,7 +1678,7 @@ create_cd_newstate (const re_dfa_t *dfa, const re_node_set *nodes,
   reg_errcode_t err;
   re_dfastate_t *newstate;
 
-  newstate = (re_dfastate_t *) calloc (sizeof (re_dfastate_t), 1);
+  newstate = (re_dfastate_t *) calloc (1, sizeof (re_dfastate_t));
   if (BE (newstate == NULL, 0))
     return NULL;
   err = re_node_set_init_copy (&newstate->nodes, nodes);
diff --git a/compat/regex/regexec.c b/compat/regex/regexec.c
index 49358ae475c1f7..e92be5741d14c5 100644
--- a/compat/regex/regexec.c
+++ b/compat/regex/regexec.c
@@ -2796,8 +2796,8 @@ get_subexp (re_match_context_t *mctx, int bkref_node, int bkref_str_idx)
 	    continue; /* No.  */
 	  if (sub_top->path == NULL)
 	    {
-	      sub_top->path = calloc (sizeof (state_array_t),
-				      sl_str - sub_top->str_idx + 1);
+	      sub_top->path = calloc (sl_str - sub_top->str_idx + 1,
+				      sizeof (state_array_t));
 	      if (sub_top->path == NULL)
 		return REG_ESPACE;
 	    }
@@ -3361,7 +3361,7 @@ build_trtable (const re_dfa_t *dfa, re_dfastate_t *state)
       if (ndests == 0)
 	{
 	  state->trtable = (re_dfastate_t **)
-	    calloc (sizeof (re_dfastate_t *), SBC_MAX);
+	    calloc (SBC_MAX, sizeof (re_dfastate_t *));
 	  return 1;
 	}
       return 0;
@@ -3457,7 +3457,7 @@ build_trtable (const re_dfa_t *dfa, re_dfastate_t *state)
 	 discern by looking at the character code: allocate a
 	 256-entry transition table.  */
       trtable = state->trtable =
-	(re_dfastate_t **) calloc (sizeof (re_dfastate_t *), SBC_MAX);
+	(re_dfastate_t **) calloc (SBC_MAX, sizeof (re_dfastate_t *));
       if (BE (trtable == NULL, 0))
 	goto out_free;
 
@@ -3488,7 +3488,7 @@ build_trtable (const re_dfa_t *dfa, re_dfastate_t *state)
 	 transition tables, one starting at trtable[0] and one
 	 starting at trtable[SBC_MAX].  */
       trtable = state->word_trtable =
-	(re_dfastate_t **) calloc (sizeof (re_dfastate_t *), 2 * SBC_MAX);
+	(re_dfastate_t **) calloc (2 * SBC_MAX, sizeof (re_dfastate_t *));
       if (BE (trtable == NULL, 0))
 	goto out_free;
 
diff --git a/git-compat-util.h b/git-compat-util.h
index 8b3c755bf301fc..504e2787dc04d5 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -166,7 +166,7 @@ struct strbuf;
 /* Approximation of the length of the decimal representation of this type. */
 #define decimal_length(x)	((int)(sizeof(x) * 2.56 + 0.5) + 1)
 
-#ifdef __MINGW64__
+#if defined(__MINGW32__) || defined(__MINGW64__)
 #define _POSIX_C_SOURCE 1
 #elif defined(__sun__)
  /*