From 31ba9e773c604fe909c711bdc32a7f74ab7b86a2 Mon Sep 17 00:00:00 2001
From: Gleb Mazovetskiy <glex.spb@gmail.com>
Date: Wed, 9 Oct 2019 11:53:15 +0100
Subject: [PATCH] CMake: Explicitly enable POSIX extensions

This is needed when compiling on non-Linux platforms, such as Amiga,
Switch, etc.
---
 CMakeLists.txt | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index bf235bb9e..11b4563ea 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -326,6 +326,11 @@ if(WIN32)
   endif()
 endif()
 
+if(NOT WIN32 AND NOT APPLE)
+  # Enable POSIX extensions such as `readlink` and `ftruncate`.
+  add_definitions(-D_POSIX_C_SOURCE=200809L)
+endif()
+
 if(HAIKU)
   target_link_libraries(devilutionx PRIVATE network)
 endif()