mbedtls entropy: Segmentation fault on init - c

Question

I'm currently working on a projet using mbedtls and specifically, I'm tring to set up an entropy context that would allow me to start a random number generator.
Trying to understand the mechanism, I looked at the sample program gen_entropy.
Although the pre-compiled executable does run properly, when I'm compiling the same gen_entropy.c file with gcc -o new_gen_entropy gen_entropy.c, I'm immediately getting a segfault. Same goes for my own program.
Has anyone encountered the same issue?
Could you please share a way to overcome that difficulty?
gen_entropy.c
/**
* \brief Use and generate multiple entropies calls into a file
*
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* This file is part of mbed TLS (https://tls.mbed.org)
*/
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdio.h>
#define mbedtls_fprintf fprintf
#define mbedtls_printf printf
#endif
#if defined(MBEDTLS_ENTROPY_C) && defined(MBEDTLS_FS_IO)
#include "mbedtls/entropy.h"
#include <stdio.h>
#endif
#if !defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_FS_IO)
int main( void )
{
mbedtls_printf("MBEDTLS_ENTROPY_C and/or MBEDTLS_FS_IO not defined.\n");
return( 0 );
}
#else
int main( int argc, char *argv[] )
{
FILE *f;
int i, k, ret;
mbedtls_entropy_context entropy;
unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
if( argc < 2 )
{
mbedtls_fprintf( stderr, "usage: %s <output filename>\n", argv[0] );
return( 1 );
}
if( ( f = fopen( argv[1], "wb+" ) ) == NULL )
{
mbedtls_printf( "failed to open '%s' for writing.\n", argv[1] );
return( 1 );
}
mbedtls_entropy_init( &entropy );
for( i = 0, k = 768; i < k; i++ )
{
ret = mbedtls_entropy_func( &entropy, buf, sizeof( buf ) );
if( ret != 0 )
{
mbedtls_printf("failed!\n");
goto cleanup;
}
fwrite( buf, 1, sizeof( buf ), f );
mbedtls_printf( "Generating %ldkb of data in file '%s'... %04.1f" \
"%% done\r", (long)(sizeof(buf) * k / 1024), argv[1], (100 * (float) (i + 1)) / k );
fflush( stdout );
}
ret = 0;
cleanup:
mbedtls_printf( "\n" );
fclose( f );
mbedtls_entropy_free( &entropy );
return( ret );
}
#endif /* MBEDTLS_ENTROPY_C */