Add _buf() functions to bypass static string buffers

We have a number of static buffers in use in libosmo*.  This means
the related functions are not usable in a thread-safe way.  While
we so far don't have many multi-threaded programs in the osmocom
universe, the static buffers also prevent us from calling the same
e.g. string-ify function twice within a single printf() call.

Let's make sure there's an alternative function in all those cases,
where the user can pass in a caller-allocated buffer + size, and make
the 'classic' function with the static buffer a wrapper around that
_buf() variant.

Change-Id: Ibf85f79e93244f53b2684ff6f1095c5b41203e05
diff --git a/include/osmocom/gsm/gsm0808_utils.h b/include/osmocom/gsm/gsm0808_utils.h
index dedb029..e246967 100644
--- a/include/osmocom/gsm/gsm0808_utils.h
+++ b/include/osmocom/gsm/gsm0808_utils.h
@@ -69,7 +69,9 @@
 };
 
 char *osmo_lcls_dump(const struct osmo_lcls *lcls);
+char *osmo_lcls_dump_buf(char *buf, size_t buf_len, const struct osmo_lcls *lcls);
 char *osmo_gcr_dump(const struct osmo_lcls *lcls);
+char *osmo_gcr_dump_buf(char *buf, size_t buf_len, const struct osmo_lcls *lcls);
 
 extern const struct value_string gsm0808_cell_id_discr_names[];
 static inline const char *gsm0808_cell_id_discr_name(enum CELL_IDENT id_discr)
@@ -251,5 +253,6 @@
 }
 
 const char *gsm0808_channel_type_name(const struct gsm0808_channel_type *ct);
+char *gsm0808_channel_type_name_buf(char *buf, size_t buf_len, const struct gsm0808_channel_type *ct);
 
 /*! @} */