diff --git a/Source/ThirdParty/Assimp/contrib/zlib/gzguts.h b/Source/ThirdParty/Assimp/contrib/zlib/gzguts.h
index 6378d468a..c8563db52 100644
--- a/Source/ThirdParty/Assimp/contrib/zlib/gzguts.h
+++ b/Source/ThirdParty/Assimp/contrib/zlib/gzguts.h
@@ -38,6 +38,9 @@
 #if defined(__TURBOC__) || defined(_MSC_VER) || defined(_WIN32)
 #  include <io.h>
 #endif
+#ifdef __APPLE__
+#  include <unistd.h>
+#endif
 
 #if defined(_WIN32)
 #  define WIDECHAR
diff --git a/Source/ThirdParty/Civetweb/src/civetweb.c b/Source/ThirdParty/Civetweb/src/civetweb.c
index 4d26e0a83..2bd577e81 100644
--- a/Source/ThirdParty/Civetweb/src/civetweb.c
+++ b/Source/ThirdParty/Civetweb/src/civetweb.c
@@ -167,6 +167,8 @@ mg_static_assert(sizeof(void *) >= sizeof(int), "data type size check");
 
 #endif
 
+#include <stdlib.h>
+
 #if !defined(DEBUG_TRACE)
 #if defined(DEBUG)