MINOR: deinit: release the in-memory copy of shared libs

When shared libs were loaded via "set-dumpable libs", better release
them upon deinit, it will make valgrind happier. For this we now have
a new function free_collected_libs() in tools.c and call it in deinit().

include/haproxy/tools.h

@@ -1154,6 +1154,7 @@ void *get_sym_curr_addr(const char *name);
 void *get_sym_next_addr(const char *name);
 int dump_libs(struct buffer *output, int with_addr);
 void collect_libs(void);
+void free_collected_libs(void);
 
 /* Note that this may result in opening libgcc() on first call, so it may need
  * to have been called once before chrooting.

src/haproxy.c

@@ -2956,7 +2956,7 @@ void deinit(void)
 		free(init_env);
 	}
 	free(progname);
-
+	free_collected_libs();
 } /* end deinit() */
 
 __attribute__((noreturn)) void deinit_and_exit(int status)

src/tools.c

@@ -6151,6 +6151,17 @@ void collect_libs(void)
 	/* don't need the temporary storage anymore */
 	ha_free(&ctx.storage);
 }
+
+/* release memory associated to collected libs */
+void free_collected_libs(void)
+{
+	if (!lib_storage || !lib_size)
+		return;
+	munmap(lib_storage, lib_size);
+	lib_storage = NULL;
+	lib_size = 0;
+}
+
 # else // no DL_ITERATE_PHDR
 #  error "No dump_libs() function for this platform"
 # endif
@@ -6167,6 +6178,11 @@ void collect_libs(void)
 {
 }
 
+/* unsupported platform: nothing to free */
+void free_collected_libs(void)
+{
+}
+
 #endif // HA_HAVE_DUMP_LIBS
 
 /*