Merge pull request #1721 from pmienk/master

Add ax_boost_url.m4.

Author: evoskuil

m4/ax_boost_url.m4

@@ -0,0 +1,103 @@
+#
+# SYNOPSIS
+#
+#   AX_BOOST_URL
+#
+# DESCRIPTION
+#
+#   Test for the Boost.URL library from the Boost C++ Libraries. This macro
+#   checks whether the Boost.URL library is available and usable. It requires
+#   the AX_BOOST_BASE macro to be called beforehand to set up Boost paths.
+#
+#   This macro sets:
+#     - HAVE_BOOST_URL to "yes" or "no" in the configure script.
+#     - BOOST_URL_LIB to the linker flags for Boost.URL, if found.
+#
+#   If Boost.URL is not found, the macro can either error out (if required)
+#   or continue with a warning, depending on the --with-boost-url option.
+#
+# USAGE
+#
+#   AX_BOOST_BASE([1.74])  # Minimum Boost version with Boost.URL
+#   AX_BOOST_URL
+#
+# LICENSE
+#
+#   Copyright (c) 2025
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+AC_DEFUN([AX_BOOST_URL],
+[
+AC_PREREQ([2.69])
+AC_REQUIRE([AX_BOOST_BASE])
+
+AC_ARG_WITH([boost-url],
+  [AS_HELP_STRING([--with-boost-url@<:@=special-lib@:>@],
+    [use the Boost.URL library from boost - it is the first found or the one in special-lib])],
+  [],
+  [with_boost_url=yes])
+
+AS_IF([test "x$with_boost_url" != xno],
+[
+  # Save original flags
+  ax_boost_url_save_LIBS="$LIBS"
+  ax_boost_url_save_CPPFLAGS="$CPPFLAGS"
+  ax_boost_url_save_LDFLAGS="$LDFLAGS"
+
+  # Initialize variables
+  BOOST_URL_LIB=""
+  HAVE_BOOST_URL=no
+
+  # Use Boost include and library paths from AX_BOOST_BASE
+  CPPFLAGS="$CPPFLAGS $BOOST_CPPFLAGS"
+  LDFLAGS="$LDFLAGS $BOOST_LDFLAGS"
+
+  # Check for Boost.URL header
+  AC_CHECK_HEADER([boost/url.hpp],
+    [HAVE_BOOST_URL=yes],
+    [HAVE_BOOST_URL=no])
+
+  AS_IF([test "x$HAVE_BOOST_URL" = xyes],
+  [
+    # Try to find the Boost.URL library
+    # Boost.URL is header-only in newer versions, but we check for linking
+    # to ensure compatibility with older setups or custom builds
+    AC_MSG_CHECKING([whether the Boost.URL library links correctly])
+    LIBS="$LIBS -lboost_url"
+    AC_LINK_IFELSE(
+      [AC_LANG_PROGRAM([#include <boost/url.hpp>],
+        [boost::urls::url u; u.set_scheme("https");])],
+      [BOOST_URL_LIB="-lboost_url"
+       AC_MSG_RESULT([yes])],
+      [AC_MSG_RESULT([no])
+       HAVE_BOOST_URL=no])
+  ])
+
+  # Handle the result
+  AS_IF([test "x$HAVE_BOOST_URL" = xyes],
+  [
+    AC_DEFINE([HAVE_BOOST_URL], [1], [Define if Boost.URL is available])
+    AC_SUBST([BOOST_URL_LIB])
+  ],
+  [
+    if test "x$with_boost_url" = xyes; then
+      AC_MSG_ERROR([Boost.URL library not found. Try specifying --with-boost-url=/path/to/boost.])
+    else
+      AC_MSG_WARN([Boost.URL library not found; continuing without it.])
+    fi
+  ])
+
+  # Restore original flags
+  LIBS="$ax_boost_url_save_LIBS"
+  CPPFLAGS="$ax_boost_url_save_CPPFLAGS"
+  LDFLAGS="$ax_boost_url_save_LDFLAGS"
+],
+[
+  AC_MSG_NOTICE([Boost.URL support disabled by --without-boost-url])
+])
+
+]) # AX_BOOST_URL