Add some missing returncode checks to get_exec_path()

src/folder.c

@@ -32,10 +32,14 @@ static int get_exec_path (char *exec_path, const size_t exec_path_sz)
 
   const ssize_t len = readlink (tmp, exec_path, exec_path_sz - 1);
 
+  if (len == -1) return -1;
+
   #elif defined (_WIN)
 
   const DWORD len = GetModuleFileName (NULL, exec_path, exec_path_sz - 1);
 
+  if (len == 0) return -1;
+
   #elif defined (__APPLE__)
 
   u32 size = (u32) exec_path_sz;
@@ -61,6 +65,8 @@ static int get_exec_path (char *exec_path, const size_t exec_path_sz)
 
   const ssize_t len = readlink (tmp, exec_path, exec_path_sz - 1);
 
+  if (len == -1) return -1;
+
   #else
   #error Your Operating System is not supported or detected
   #endif