Clean up vestigial uses of png_size_tp
diff --git a/png.c b/png.c
index 62ab209..8fac414 100644
--- a/png.c
+++ b/png.c
@@ -2710,7 +2710,7 @@
 
 int /* PRIVATE */
 png_check_fp_number(png_const_charp string, size_t size, int *statep,
-    png_size_tp whereami)
+    size_t *whereami)
 {
    int state = *statep;
    size_t i = *whereami;
diff --git a/pngpriv.h b/pngpriv.h
index 2e426cf..b8a73b6 100644
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -1946,7 +1946,7 @@
  * the problem character.)  This has not been tested within libpng.
  */
 PNG_INTERNAL_FUNCTION(int,png_check_fp_number,(png_const_charp string,
-   size_t size, int *statep, png_size_tp whereami),PNG_EMPTY);
+   size_t size, int *statep, size_t *whereami),PNG_EMPTY);
 
 /* This is the same but it checks a complete string and returns true
  * only if it just contains a floating point number.  As of 1.5.4 this
diff --git a/pngwutil.c b/pngwutil.c
index 16345e4..01f0607 100644
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -1,7 +1,7 @@
 
 /* pngwutil.c - utilities to write a PNG file
  *
- * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2018-2022 Cosmin Truta
  * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
  * Copyright (c) 1996-1997 Andreas Dilger
  * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
@@ -1747,7 +1747,7 @@
 {
    png_uint_32 purpose_len;
    size_t units_len, total_len;
-   png_size_tp params_len;
+   size_t *params_len;
    png_byte buf[10];
    png_byte new_purpose[80];
    int i;
@@ -1769,7 +1769,7 @@
    png_debug1(3, "pCAL units length = %d", (int)units_len);
    total_len = purpose_len + units_len + 10;
 
-   params_len = (png_size_tp)png_malloc(png_ptr,
+   params_len = (size_t *)png_malloc(png_ptr,
        (png_alloc_size_t)((png_alloc_size_t)nparams * (sizeof (size_t))));
 
    /* Find the length of each parameter, making sure we don't count the