meson: Install a xml2-config script

This one does not need build-time configuration but forwards to
`pkg-config` instead. It is mostly (and hopefully sufficiently)
compatible with the script installed by autotools.

meson.build

@@ -254,7 +254,7 @@ endforeach
 # [X] libxml-2.0.pc.in
 # [X] libxml2-config.cmake.in
 # [X] python/setup.py.in
-# [N] xml2-config.in
+# [X] xml2-config.in
 
 ## config.h
 config_h = configuration_data()
@@ -600,6 +600,15 @@ configure_file(
     install_dir: dir_lib / 'cmake' / meson.project_name(),
 )
 
+## xml2-config script
+
+install_data(
+    'xml2-config-meson',
+    install_dir: dir_bin,
+    install_mode: 'rwxr-xr-x',
+    rename: 'xml2-config',
+)
+
 # summary
 
 summary(

xml2-config-meson

@@ -0,0 +1,56 @@
+#!/bin/sh
+
+usage() {
+    cat <<EOF
+${2:+$2
+
+}Usage: xml2-config <OPTION...>
+
+Options:
+  --prefix              print libxml prefix
+  --prefix=DIR          change libxml prefix
+  --libs                print library linking information
+  --dynamic             skip libraries only necessary for static linking
+  --cflags              print pre-processor and compiler flags
+  --modules             module support enabled
+  --help                display this help and exit
+  --version             output version information
+EOF
+    exit "$1"
+}
+
+if [ "$#" -lt 1 ]; then
+    usage 1 "Need at least one option."
+fi
+
+prefix=0
+set_prefix=
+libs=0
+libflag=--static
+cflags=0
+modules=0
+version=0
+
+for arg in "$@"; do
+    case $arg in
+        --prefix)   prefix=1 ;;
+        --prefix=*) set_prefix="${arg#*=}" ;;
+        --libs)     libs=1 ;;
+        --dynamic)  libflag=--shared ;;
+        --cflags)   cflags=1 ;;
+        --modules)  modules=1 ;;
+        --help)     usage 0 ;;
+        --version)  version=1 ;;
+        *)          usage 1 "Unknown option: $arg" ;;
+    esac
+done
+
+set --
+[ "$prefix"  -eq 1 ] && set -- "$@" --variable=prefix
+[ -n "$set_prefix" ] && set -- "$@" --define-variable=prefix="$set_prefix"
+[ "$libs"    -eq 1 ] && set -- "$@" --libs "$libflag"
+[ "$cflags"  -eq 1 ] && set -- "$@" --cflags
+[ "$modules" -eq 1 ] && set -- "$@" --variable=modules
+[ "$version" -eq 1 ] && set -- "$@" --modversion
+
+exec ${PKG_CONFIG:-pkg-config} "$@" libxml-2.0