cmake: Fix installation directories in libxml2-config.cmake

Use AX_RECURSIVE_EVAL with Autotools and remove hack using parent
directories.

Fixes #898.

configure.ac

@@ -1140,6 +1140,17 @@ dnl for the spec file
 RELDATE=`date +'%a %b %e %Y'`
 AC_SUBST(RELDATE)
 
+# for libxml2-config.cmake.in
+AX_RECURSIVE_EVAL(["$bindir"], [INSTALL_BINDIR])
+AX_RECURSIVE_EVAL(["$includedir"], [INSTALL_INCLUDEDIR])
+AX_RECURSIVE_EVAL(["$libdir"], [INSTALL_LIBDIR])
+AC_SUBST(INSTALL_BINDIR)
+AC_SUBST(INSTALL_INCLUDEDIR)
+AC_SUBST(INSTALL_LIBDIR)
+AM_SUBST_NOTMAKE(INSTALL_BINDIR)
+AM_SUBST_NOTMAKE(INSTALL_INCLUDEDIR)
+AM_SUBST_NOTMAKE(INSTALL_LIBDIR)
+
 # keep on one line for cygwin c.f. #130896
 AC_CONFIG_FILES([Makefile include/Makefile include/libxml/Makefile include/private/Makefile doc/Makefile doc/devhelp/Makefile example/Makefile fuzz/Makefile python/Makefile python/tests/Makefile xstc/Makefile include/libxml/xmlversion.h libxml-2.0.pc libxml-2.0-uninstalled.pc libxml2-config.cmake])
 AC_CONFIG_FILES([python/setup.py], [chmod +x python/setup.py])

libxml2-config.cmake.in

@@ -24,20 +24,17 @@
 #   LibXml2::LibXml2          - the LibXml2 library
 #   LibXml2::xmllint          - the xmllint command-line executable
 
-get_filename_component(_libxml2_rootdir ${CMAKE_CURRENT_LIST_DIR}/../../../ ABSOLUTE)
-
 set(LIBXML2_VERSION_MAJOR  @LIBXML_MAJOR_VERSION@)
 set(LIBXML2_VERSION_MINOR  @LIBXML_MINOR_VERSION@)
 set(LIBXML2_VERSION_MICRO  @LIBXML_MICRO_VERSION@)
 set(LIBXML2_VERSION_STRING "@VERSION@")
 set(LIBXML2_DEFINITIONS    "@XML_CFLAGS@")
-set(LIBXML2_INSTALL_PREFIX ${_libxml2_rootdir})
-set(LIBXML2_INCLUDE_DIR    ${_libxml2_rootdir}/include/libxml2)
-set(LIBXML2_LIBRARY_DIR    ${_libxml2_rootdir}/lib)
+set(LIBXML2_INCLUDE_DIR    @INSTALL_INCLUDEDIR@/libxml2)
+set(LIBXML2_LIBRARY_DIR    @INSTALL_LIBDIR@)
 
 find_library(LIBXML2_LIBRARY NAMES xml2 HINTS ${LIBXML2_LIBRARY_DIR} NO_DEFAULT_PATH)
-find_program(LIBXML2_XMLCATALOG_EXECUTABLE NAMES xmlcatalog HINTS ${_libxml2_rootdir}/bin NO_DEFAULT_PATH)
-find_program(LIBXML2_XMLLINT_EXECUTABLE NAMES xmllint HINTS ${_libxml2_rootdir}/bin NO_DEFAULT_PATH)
+find_program(LIBXML2_XMLCATALOG_EXECUTABLE NAMES xmlcatalog HINTS @INSTALL_BINDIR@ NO_DEFAULT_PATH)
+find_program(LIBXML2_XMLLINT_EXECUTABLE NAMES xmllint HINTS @INSTALL_BINDIR@ NO_DEFAULT_PATH)
 
 set(LIBXML2_LIBRARIES ${LIBXML2_LIBRARY})
 set(LIBXML2_INCLUDE_DIRS ${LIBXML2_INCLUDE_DIR})

m4/ax_recursive_eval.m4

@@ -0,0 +1,56 @@
+# ===========================================================================
+#    https://www.gnu.org/software/autoconf-archive/ax_recursive_eval.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_RECURSIVE_EVAL(VALUE, RESULT)
+#
+# DESCRIPTION
+#
+#   Interpolate the VALUE in loop until it doesn't change, and set the
+#   result to $RESULT. WARNING: It's easy to get an infinite loop with some
+#   unsane input.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Alexandre Duret-Lutz <adl@gnu.org>
+#
+#   This program is free software; you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation; either version 2 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 1
+
+AC_DEFUN([AX_RECURSIVE_EVAL],
+[_lcl_receval="$1"
+$2=`(test "x$prefix" = xNONE && prefix="$ac_default_prefix"
+     test "x$exec_prefix" = xNONE && exec_prefix="${prefix}"
+     _lcl_receval_old=''
+     while test "[$]_lcl_receval_old" != "[$]_lcl_receval"; do
+       _lcl_receval_old="[$]_lcl_receval"
+       eval _lcl_receval="\"[$]_lcl_receval\""
+     done
+     echo "[$]_lcl_receval")`])

meson.build

@@ -772,6 +772,9 @@ config_cmake = configuration_data()
 config_cmake.set('LIBXML_MAJOR_VERSION', v_maj)
 config_cmake.set('LIBXML_MINOR_VERSION', v_min)
 config_cmake.set('LIBXML_MICRO_VERSION', v_mic)
+config_cmake.set('INSTALL_BINDIR', dir_bin)
+config_cmake.set('INSTALL_INCLUDEDIR', dir_include)
+config_cmake.set('INSTALL_LIBDIR', dir_lib)
 config_cmake.set('VERSION', meson.project_version())
 config_cmake.set('WITH_ICONV', iconv_dep.found().to_int().to_string())
 config_cmake.set('WITH_ICU', icu_dep.found().to_int().to_string())