Use casts when doing nonstandard pointer conversions

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/programs/test/metatest.c b/programs/test/metatest.c
index eb3bb76..36119f6 100644
--- a/programs/test/metatest.c
+++ b/programs/test/metatest.c
@@ -45,7 +45,7 @@
 {
     (void) name;
     volatile char *p;
-    mbedtls_platform_zeroize(&p, sizeof(p));
+    mbedtls_platform_zeroize((void *) &p, sizeof(p));
     mbedtls_printf("%p -> %u\n", p, (unsigned) *p);
 }
 
@@ -54,7 +54,7 @@
     (void) name;
     unsigned (*p)(void);
     mbedtls_platform_zeroize(&p, sizeof(p));
-    mbedtls_printf("%p() -> %u\n", p, p());
+    mbedtls_printf("%p() -> %u\n", (void *) p, p());
 }