alloca.h is not universally available
diff --git a/configure.ac b/configure.ac
index ce85ebf..64a37a9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -92,6 +92,7 @@
dnl Checks for header files.
AC_HEADER_STDC
AC_CHECK_HEADERS(sys/param.h)
+AC_CHECK_HEADERS(alloca.h)
dnl Checks for typedefs, structures, and compiler characteristics.
AC_C_BIGENDIAN
diff --git a/skeletons/asn_system.h b/skeletons/asn_system.h
index a9c4ad3..24d8da7 100644
--- a/skeletons/asn_system.h
+++ b/skeletons/asn_system.h
@@ -15,13 +15,16 @@
#include <stdio.h> /* For snprintf(3) */
#include <stdlib.h> /* For *alloc(3) */
-#include <alloca.h> /* For alloca(3) */
#include <string.h> /* For memcpy(3) */
#include <sys/types.h> /* For size_t */
#include <limits.h> /* For LONG_MAX */
#include <stdarg.h> /* For va_start */
#include <stddef.h> /* for offsetof and ptrdiff_t */
+#ifdef HAVE_ALLOCA_H
+#include <alloca.h> /* For alloca(3) */
+#endif
+
#ifdef _WIN32
#include <malloc.h>