remove the assumption that game is ran from cwd at root

src/system/linux/twn_elf.c

@@ -1,5 +1,6 @@
 #include "twn_elf.h"
 #include "twn_game_object_c.h"
+#include "twn_engine_context_c.h"
 
 #include <fcntl.h>
 #include <unistd.h>
@@ -9,6 +10,8 @@
 #define __USE_GNU
 #include <dlfcn.h>
 
+#include <SDL2/SDL.h>
+
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -33,7 +36,8 @@ bool infer_elf_section_bounds(const char *const restrict name,
     } else {
         /* dynamically linked */
         from_shared_object = true;
-        memcpy(buf, "libgame.so", sizeof "libgame.so");
+        if (SDL_snprintf(buf, sizeof buf, "%s%s", ctx.base_dir, "libgame.so") < 0)
+            goto ERR_CANT_APPEND_BASE_PATH;
     }
 
     int elf = open(buf, O_RDONLY);
@@ -84,6 +88,7 @@ ERR_NOT_ELF:
     close(elf);
 
 ERR_CANT_OPEN_SELF:
+ERR_CANT_APPEND_BASE_PATH:
 ERR_CANT_READLINK:
     return result;
 }