1 files changed, 19 insertions, 0 deletions

diff --git a/gl/m4/byteswap.m4 b/gl/m4/byteswap.m4
new file mode 100644
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--- /dev/null
+++ b/gl/m4/byteswap.m4
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+# byteswap.m4 serial 4
+dnl Copyright (C) 2005, 2007, 2009-2021 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Oskar Liljeblad.
+
+AC_DEFUN([gl_BYTESWAP],
+[
+  dnl Prerequisites of lib/byteswap.in.h.
+  AC_CHECK_HEADERS([byteswap.h], [
+    BYTESWAP_H=''
+  ], [
+    BYTESWAP_H='byteswap.h'
+  ])
+  AC_SUBST([BYTESWAP_H])
+  AM_CONDITIONAL([GL_GENERATE_BYTESWAP_H], [test -n "$BYTESWAP_H"])
+])