Support for PC platform (#12)

* improvements for cross-platform compiling

* moved tactility-core to libs/

* splitup improvements

* remove git/gitmodules from freertos

* better platformbetter platform checks

* added build scripts

* delete mbedtls

* re-add mbedtls

* fixes and improvements

* added pc build

* simplify build scripts

* revert build scrpit

* updated builds

* fix for pc

* fix for pc

* fix for build

libs/mbedtls/tests/include/alt-dummy/threading_alt.h

@@ -0,0 +1,14 @@
+/* threading_alt.h with dummy types for MBEDTLS_THREADING_ALT */
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+#ifndef THREADING_ALT_H
+#define THREADING_ALT_H
+
+typedef struct mbedtls_threading_mutex_t {
+    int dummy;
+} mbedtls_threading_mutex_t;
+
+#endif /* threading_alt.h */