$NetBSD: patch-src_ptex_CMakeLists.txt,v 1.1 2023/11/07 17:56:56 nros Exp $

alloca.h is non standard, check if it can be included 

--- src/ptex/CMakeLists.txt.orig	2022-08-05 02:02:51.000000000 +0000
+++ src/ptex/CMakeLists.txt
@@ -1,3 +1,9 @@
+include(CheckIncludeFileCXX)
+check_include_file_cxx("alloca.h" HAVE_ALLOCA_H)
+if(HAVE_ALLOCA_H)
+add_compile_definitions(PTEX_HAVE_ALLOCA_H)
+endif()
+
 configure_file(PtexVersion.h.in
     ${CMAKE_CURRENT_SOURCE_DIR}/PtexVersion.h @ONLY)