Allow building with the -Wunused flag

Make some functions non-static, to avoid Wunused function warnings. Make
a function scoped variable block scoped instead, to avoid Wunused
variable warnings in some configurations.
diff --git a/tests/suites/test_suite_entropy.function b/tests/suites/test_suite_entropy.function
index 0b1cfe8..46137da 100644
--- a/tests/suites/test_suite_entropy.function
+++ b/tests/suites/test_suite_entropy.function
@@ -48,7 +48,7 @@
  * This might break memory checks in the future if sources need 'free-ing' then
  * as well.
  */
-static void entropy_clear_sources( mbedtls_entropy_context *ctx )
+void entropy_clear_sources( mbedtls_entropy_context *ctx )
 {
     ctx->source_count = 0;
 }
@@ -58,7 +58,7 @@
  */
 static unsigned char buffer_seed[MBEDTLS_ENTROPY_BLOCK_SIZE];
 
-static int buffer_nv_seed_read( unsigned char *buf, size_t buf_len )
+int buffer_nv_seed_read( unsigned char *buf, size_t buf_len )
 {
     if( buf_len != MBEDTLS_ENTROPY_BLOCK_SIZE )
         return( -1 );
@@ -67,7 +67,7 @@
     return( 0 );
 }
 
-static int buffer_nv_seed_write( unsigned char *buf, size_t buf_len )
+int buffer_nv_seed_write( unsigned char *buf, size_t buf_len )
 {
     if( buf_len != MBEDTLS_ENTROPY_BLOCK_SIZE )
         return( -1 );
@@ -98,7 +98,7 @@
     return( 0 );
 }
 
-static int read_nv_seed( unsigned char *buf, size_t buf_len )
+int read_nv_seed( unsigned char *buf, size_t buf_len )
 {
     FILE *f;