--- qsampler/trunk/configure.ac	2015/08/12 16:57:14	2834
+++ qsampler/trunk/configure.ac	2021/04/15 13:28:01	3873
@@ -1,24 +1,81 @@
 # Process this file with autoconf to produce a configure script.
-AC_INIT(Qsampler, 0.3.1.2, rncbc@rncbc.org, qsampler)
+AC_INIT(Qsampler, 0.9.3, rncbc@rncbc.org, qsampler)
 
 AC_CONFIG_SRCDIR(src/qsampler.cpp)
 AC_CONFIG_HEADERS(src/config.h)
-AC_CONFIG_FILES(Makefile qsampler.spec src/src.pri src/qsampler.desktop)
+AC_CONFIG_FILES(Makefile qsampler.spec src/src.pri)
+
+# Build version string.
+AC_CACHE_VAL([ac_cv_build_version], [
+   ac_cv_build_version=$(git describe --tags --dirty --abbrev=6 2>/dev/null)
+   if test -n "$ac_cv_build_version"; then
+      ac_cv_build_version=$(echo $ac_cv_build_version | sed 's/^[[^0-9]]\+//')
+      ac_cv_build_version=$(echo $ac_cv_build_version | sed 's/^1_//')
+      ac_cv_build_version=$(echo $ac_cv_build_version | sed 's/^[[_vV]]\+//')
+      ac_cv_build_version=$(echo $ac_cv_build_version | sed 's/-g/git./')
+      ac_cv_build_version=$(echo $ac_cv_build_version | sed 's/[[_|-]]/./g')
+      ac_cv_build_version_extra=$(git rev-parse --abbrev-ref HEAD 2>/dev/null)
+      if test "x$ac_cv_build_version_extra" != "xmaster"; then
+         ac_cv_build_version="$ac_cv_build_version [[$ac_cv_build_version_extra]]"
+      fi
+   else
+      ac_cv_build_version=$PACKAGE_VERSION
+   fi
+])
+ac_build_version="$ac_cv_build_version"
+AC_DEFINE_UNQUOTED(CONFIG_BUILD_VERSION, ["$ac_build_version"], [Build version string.])
+
+# Sanitized version string.
+AC_CACHE_VAL([ac_cv_version], [
+   ac_cv_version=$(echo $PACKAGE_VERSION | sed -r 's/^([[0-9|\.]]+).*$/\1/')
+])
+ac_version="$ac_cv_version"
+AC_DEFINE_UNQUOTED(CONFIG_VERSION, ["$ac_version"], [Version string.])
+AC_SUBST(ac_version)
 
 # Set default installation prefix.
 AC_PREFIX_DEFAULT(/usr/local)
-ac_prefix=$prefix
-if test "x$ac_prefix" = "xNONE"; then
-    ac_prefix=$ac_default_prefix
+if test "x$prefix" = "xNONE"; then
+   prefix=$ac_default_prefix
+fi
+if test "x$exec_prefix" = "xNONE"; then
+   exec_prefix=$prefix
 fi
+eval ac_prefix=$prefix
 AC_SUBST(ac_prefix)
 AC_DEFINE_UNQUOTED(CONFIG_PREFIX, ["$ac_prefix"], [Default installation prefix.])
 
+# Set default installation directories.
+eval ac_bindir=$bindir
+AC_SUBST(ac_bindir)
+AC_DEFINE_UNQUOTED(CONFIG_BINDIR, ["$ac_bindir"], [Default executable binary path.])
+
+eval ac_libdir=$libdir
+AC_SUBST(ac_libdir)
+AC_DEFINE_UNQUOTED(CONFIG_LIBDIR, ["$ac_libdir"], [Default object library path.])
+
+eval datarootdir=$datarootdir
+eval ac_datadir=$datadir
+AC_SUBST(ac_datadir)
+AC_DEFINE_UNQUOTED(CONFIG_DATADIR, ["$ac_datadir"], [Default arch-idependent data path.])
+
+eval ac_mandir=$mandir
+AC_SUBST(ac_mandir)
+AC_DEFINE_UNQUOTED(CONFIG_MANDIR, ["$ac_mandir"], [Default man page path.])
+
+
 # Enable debugging argument option.
 AC_ARG_ENABLE(debug,
-  AC_HELP_STRING([--enable-debug], [enable debugging (default=no)]),
+  AS_HELP_STRING([--enable-debug], [enable debugging (default=no)]),
   [ac_debug="$enableval"])
 
+# Enable Qt6 build preference.
+AC_ARG_ENABLE(qt6,
+  AS_HELP_STRING([--enable-qt6], [enable Qt6 build (default=no)]),
+  [ac_qt6="$enableval"],
+  [ac_qt6="no"])
+
+
 if test "x$ac_debug" = "xyes"; then
    AC_DEFINE(CONFIG_DEBUG, 1, [Define if debugging is enabled.])
    ac_stacktrace="yes"
@@ -30,72 +87,47 @@
 AC_SUBST(ac_debug)
 
 
-# Enable Qt4/5 availability.
-AC_ARG_ENABLE(qt4,
-  AC_HELP_STRING([--enable-qt4], [enable Qt4 build (default=no)]),
-  [ac_qt4="$enableval"],
-  [ac_qt4="no"])
-
-AC_ARG_ENABLE(qt5,
-  AC_HELP_STRING([--enable-qt5], [enable Qt5 build (default=yes)]),
-  [ac_qt5="$enableval"],
-  [ac_qt5="yes"])
-
-
-
 # Enable libgig availability.
 AC_ARG_ENABLE(libgig,
-  AC_HELP_STRING([--enable-libgig], [enable libgig interface (default=yes)]),
+  AS_HELP_STRING([--enable-libgig], [enable libgig interface (default=yes)]),
   [ac_libgig="$enableval"],
   [ac_libgig="yes"])
 
+# Enable unique/single instance.
+AC_ARG_ENABLE(xunique,
+  AS_HELP_STRING([--enable-xunique], [enable unique/single instance (default=yes)]),
+  [ac_xunique="$enableval"],
+  [ac_xunique="yes"])
+
 # Enable debugger stack-trace option (assumes --enable-debug).
 AC_ARG_ENABLE(stacktrace,
-  AC_HELP_STRING([--enable-stacktrace], [enable debugger stack-trace (default=no)]),
+  AS_HELP_STRING([--enable-stacktrace], [enable debugger stack-trace (default=no)]),
   [ac_stacktrace="$enableval"])
 
 
 # Standard installation base dirs.
-if test "$cross_compiling" = yes; then
-  ac_with_paths=""
-else
-  ac_with_paths="/usr /usr/local"
-fi
-
-# Set for alternate Qt4/5 installation dir.
-AC_ARG_WITH(qt4,
-  AC_HELP_STRING([--with-qt4=PATH], [use alternate Qt4 install path]),
-  [ac_qt4_path="$withval"], [ac_qt4_path="no"])
-
-AC_ARG_WITH(qt5,
-  AC_HELP_STRING([--with-qt5=PATH], [use alternate Qt5 install path]),
-  [ac_qt5_path="$withval"], [ac_qt5_path="no"])
-
-if test "x$ac_qt4_path" != "xno"; then
-   ac_with_paths="$ac_with_paths $ac_qt4_path"
-   ac_qt4="yes"
-fi
-
-if test "x$ac_qt5_path" != "xno"; then
-   ac_with_paths="$ac_with_paths $ac_qt5_path"
-   ac_qt5="yes"
-fi
+ac_path=$PATH
+ac_pkg_config_path=$PKG_CONFIG_PATH
+ac_with_paths=""
 
-if test "x$ac_qt5" = "xno"; then
-   ac_qt4="yes"
-fi
-if test "x$ac_qt4" = "xyes"; then
-   ac_qt5="no"
+# Set for alternate Qt installation dir.
+AC_ARG_WITH(qt,
+  AS_HELP_STRING([--with-qt=PATH], [use alternate Qt install path]),
+  [ac_qt_path="$withval"], [ac_qt_path="no"])
+
+if test "x$ac_qt_path" != "xno"; then
+   ac_path="$ac_qt_path/bin:$ac_path"
+   ac_pkg_config_path="$ac_qt_path/lib/pkgconfig:$ac_pkg_config_path"
 fi
 
 # Set for alternate liblscp installation dir.
 AC_ARG_WITH(liblscp,
-  AC_HELP_STRING([--with-liblscp=PATH], [use alternate liblscp install path]),
+  AS_HELP_STRING([--with-liblscp=PATH], [use alternate liblscp install path]),
   [ac_with_paths="$ac_with_paths $withval"])
 
 # Set for alternate libgig installation dir.
 AC_ARG_WITH(libgig,
-  AC_HELP_STRING([--with-libgig=PATH], [use alternate libgig install path]),
+  AS_HELP_STRING([--with-libgig=PATH], [use alternate libgig install path]),
   [ac_with_paths="$ac_with_paths $withval"])
 
 
@@ -105,20 +137,35 @@
 
 
 # Checks for programs.
-AC_PROG_CC
 AC_PROG_CPP
 AC_PROG_CXX
 AC_PROG_CXXCPP
-AC_PROG_GCC_TRADITIONAL
 
 # Checks for languages.
-AC_LANG_C
 AC_LANG_CPLUSPLUS
 
+# Check for pkg-config.
 PKG_PROG_PKG_CONFIG
 
+# Check whether -std=c++11 support is necessary (4 < g++ version < 6).
+AC_CACHE_CHECK([for g++ major version], [ac_cv_gxx_version_major], [
+   ac_cv_gxx_version_major=$($CC -dumpversion)
+   if test -n "$ac_cv_gxx_version_major"; then
+      ac_cv_gxx_version_major=$(echo $ac_cv_gxx_version_major | cut -d'.' -f1);
+   fi
+   ac_gxx_version_major=$(($ac_cv_gxx_version_major + 0))
+])
+ac_gxx_version_major=$ac_cv_gxx_version_major
+if test $ac_gxx_version_major -ge 4 -a $ac_gxx_version_major -lt 6; then
+   CXXFLAGS="-std=c++11 $CXXFLAGS"
+   ac_cflags="-std=c++11 $ac_cflags"
+elif test $ac_gxx_version_major -ge 6 -a $ac_gxx_version_major -lt 11; then
+   CXXFLAGS="-std=c++17 $CXXFLAGS"
+   ac_cflags="-std=c++17 $ac_cflags"
+fi
+
 # Check for proper flags.
-ac_arch=`uname -m`
+ac_arch=$(uname -m)
 
 # Check for install paths and alternatives...
 ac_libdirs="lib"
@@ -131,58 +178,84 @@
 CPPFLAGS="-fPIC $CPPFLAGS"
 
 # Prepend alternate dependencies paths.
-ac_path=$PATH
-
 for X in $ac_with_paths; do
   if test -d $X/bin; then
-    ac_path="$X/bin:$ac_path"
+     ac_path="$X/bin:$ac_path"
   fi
   if test -d $X/include; then
-    CFLAGS="-I$X/include $CFLAGS "
-    CPPFLAGS="-I$X/include $CPPFLAGS"
-    ac_incpath="$X/include $ac_incpath"
+     CFLAGS="-I$X/include $CFLAGS "
+     CPPFLAGS="-I$X/include $CPPFLAGS"
+     ac_incpath="$X/include $ac_incpath"
   fi
   for Y in $ac_libdirs; do
-    if test -d $X/$Y; then
-       LIBS="-L$X/$Y $LIBS"
-       ac_libs="-L$X/$Y $ac_libs"
-    fi
+     if test -d $X/$Y; then
+        LIBS="-L$X/$Y $LIBS"
+        ac_libs="-L$X/$Y $ac_libs"
+        if test -d $X/$Y/pkgconfig; then
+           ac_pkg_config_path="$X/$Y/pkgconfig:$ac_pkg_config_path"
+        fi
+     fi
   done
 done
 
+# Set pkg-config path.
+if test -n "$ac_pkg_config_path"; then
+   export PKG_CONFIG_PATH=$ac_pkg_config_path
+fi
+
+
 # A common error message:
 ac_errmsg="not found in current PATH. Maybe QT development environment isn't available."
 
-if test "x$ac_qt4" = "xyes"; then
-   AC_PATH_PROG(ac_qmake, qmake-qt4, [no], $ac_path)
-fi
-if test "x$ac_qt5" = "xyes"; then
-   AC_PATH_PROG(ac_qmake, qmake-qt5, [no], $ac_path)
-fi
-if test "x$ac_qmake" = "xno"; then
-   AC_PATH_PROG(ac_cv_qmake, qmake, [no], $ac_path)
-   ac_qmake=$ac_cv_qmake
+# Check for qtchooser availability.
+AC_PATH_TOOL(ac_qtchooser, qtchooser, [no], $ac_path)
+if test -x $ac_qtchooser; then
+   if test "x$ac_qt6" = "xyes"; then
+      export QT_SELECT=6
+   else
+      export QT_SELECT=5
+   fi
 fi
+
+# Check for proper qmake path/version alternatives.
+AC_PATH_TOOL(ac_qmake, qmake, [no], $ac_path)
 if test "x$ac_qmake" = "xno"; then
-   AC_MSG_ERROR([qmake $ac_errmsg])
+   if test "x$ac_qt6" = "xyes"; then
+      AC_PATH_TOOL(ac_cv_qmake, qmake-qt6, [no], $ac_path)
+      ac_qmake=$ac_cv_qmake
+   else
+      AC_PATH_TOOL(ac_cv_qmake, qmake-qt5, [no], $ac_path)
+      ac_qmake=$ac_cv_qmake
+   fi
 fi
 
-# Check for proper Qt4/5 major version.
-ac_qt_version_major=`$ac_qmake -query QT_VERSION | cut -d. -f1`
-if test "x$ac_qt4" = "xyes" -a "x$ac_qt_version_major" != "x4"; then
-   AC_MSG_ERROR([qmake-qt4 $ac_errmsg (qt4-devel)])
-fi
-if test "x$ac_qt5" = "xyes" -a "x$ac_qt_version_major" != "x5"; then
-   AC_MSG_ERROR([qmake-qt5 $ac_errmsg (qt5-devel)])
+# Check for proper Qt major version.
+AC_CACHE_CHECK([for Qt major version], [ac_cv_qt_version_major], [
+   ac_cv_qt_version=$($ac_qmake -query QT_VERSION)
+   ac_cv_qt_version_major=$(echo $ac_cv_qt_version | cut -d'.' -f1)
+   ac_cv_qt_version_major=$(($ac_cv_qt_version_major + 0))
+])
+ac_qt_version=$ac_cv_qt_version
+ac_qt_version_major=$ac_cv_qt_version_major
+if test "x$ac_qmake" = "xno"; then
+   if test $ac_qt_version_major -lt 6; then
+      AC_MSG_ERROR([qmake-qt5 $ac_errmsg (qt5-devel)])
+   else
+      AC_MSG_ERROR([qmake-qt6 $ac_errmsg (qt6-devel)])
+   fi
 fi
 
-ac_qt_install_bins=`$ac_qmake -query QT_INSTALL_BINS`
-if test -d $ac_qt_install_bins; then
-   ac_path="$ac_qt_install_bins:$ac_path"
+# Check for proper Qt install path.
+AC_CACHE_CHECK([for Qt install path], [ac_cv_qt_install_path], [
+   ac_cv_qt_install_path=$($ac_qmake -query QT_INSTALL_BINS)
+])
+ac_qt_install_path=$ac_cv_qt_install_path
+if test -d $ac_qt_install_path; then
+   ac_path="$ac_qt_install_path:$ac_path"
 fi
 
 # Check it again, now with updated PATH, just in case...
-AC_PATH_PROG(ac_cv_qmake, qmake, [no], $ac_path)
+AC_PATH_TOOL(ac_cv_qmake, qmake, [no], $ac_path)
 ac_qmake=$ac_cv_qmake
 if test "x$ac_qmake" = "xno"; then
    AC_MSG_ERROR([qmake $ac_errmsg])
@@ -190,73 +263,90 @@
 
 AC_SUBST(ac_qmake)
 
-ac_qt_install_headers=`$ac_qmake -query QT_INSTALL_HEADERS`
+AC_CACHE_CHECK([for Qt install headers], [ac_cv_qt_install_headers], [
+   ac_cv_qt_install_headers=$($ac_qmake -query QT_INSTALL_HEADERS)
+])
+ac_qt_install_headers=$ac_cv_qt_install_headers
 if test -d $ac_qt_install_headers; then
    CFLAGS="-I$ac_qt_install_headers $CFLAGS "
    CPPFLAGS="-I$ac_qt_install_headers $CPPFLAGS"
    ac_incpath="$ac_qt_install_headers $ac_incpath"
 fi
 
-ac_qt_install_libs=`$ac_qmake -query QT_INSTALL_LIBS`
+AC_CACHE_CHECK([for Qt install libraries], [ac_cv_qt_install_libs], [
+   ac_cv_qt_install_libs=$($ac_qmake -query QT_INSTALL_LIBS)
+])
+ac_qt_install_libs=$ac_cv_qt_install_libs
 if test -d $ac_qt_install_libs; then
    LIBS="-L$ac_qt_install_libs $LIBS"
    ac_libs="-L$ac_qt_install_libs $ac_libs"
 fi
 
-# Check for proper Qt4/5 version.
-if test "x$ac_qt4" = "xyes"; then
-   AC_CACHE_CHECK([for Qt library version >= 4.4],
-      ac_cv_qtversion, [
-      AC_TRY_LINK([#include "QtCore/qglobal.h"], [
-         #if QT_VERSION < 0x040400 || QT_VERSION >= 0x050000
-         #error Qt library 4.4 or greater required.
-         #endif
-      ], ac_cv_qtversion="yes", [
-         echo "no; Qt 4.4 or greater is required"
-         exit 1
-      ])
+# Finally, check for proper Qt version.
+AC_CACHE_CHECK([for Qt library version >= 5.1],
+   ac_cv_qtversion, [
+   AC_TRY_COMPILE([#include "QtCore/qglobal.h"], [
+      #if QT_VERSION < 0x050100
+      #error Qt library 5.1 or greater required.
+      #endif
+   ], ac_cv_qtversion="yes", [
+      echo "no; Qt 5.1 or greater is required"
+      exit 1
    ])
-fi
- 
-if test "x$ac_qt5" = "xyes"; then
-   AC_CACHE_CHECK([for Qt library version >= 5.1],
-      ac_cv_qtversion, [
-      AC_TRY_LINK([#include "QtCore/qglobal.h"], [
-         #if QT_VERSION < 0x050100 || QT_VERSION >= 0x060000
-         #error Qt library 5.1 or greater required.
-         #endif
-      ], ac_cv_qtversion="yes", [
-         echo "no; Qt 5.1 or greater is required"
-         exit 1
-      ])
-   ])
-fi
+])
 
 # Check for Qt moc utility.
-AC_PATH_PROG(ac_moc, moc, [no], $ac_path)
+AC_PATH_TOOL(ac_moc, moc, [no], $ac_path)
 if test "x$ac_moc" = "xno"; then
    AC_MSG_ERROR([moc $ac_errmsg])
 fi
 AC_SUBST(ac_moc)
 
 # Check for Qt uic utility.
-AC_PATH_PROG(ac_uic, uic, [no], $ac_path)
+AC_PATH_TOOL(ac_uic, uic, [no], $ac_path)
 if test "x$ac_uic" = "xno"; then
    AC_MSG_ERROR([uic $ac_errmsg])
 fi
 AC_SUBST(ac_uic)
 
+
 # Check for Qt lupdate utility.
-AC_PATH_PROG(ac_lupdate, lupdate, [no], $ac_path)
+AC_PATH_TOOL(ac_lupdate, lupdate, [no], $ac_path)
 if test "x$ac_lupdate" = "xno"; then
-   AC_MSG_ERROR([lupdate $ac_errmsg])
+   if test $ac_qt_version_major -lt 6; then
+      AC_PATH_TOOL(ac_cv_lupdate, lupdate-qt5, [no], $ac_path)
+   else
+      AC_PATH_TOOL(ac_cv_lupdate, lupdate-qt6, [no], $ac_path)
+   fi
+   if test "x$ac_cv_lupdate" = "xno"; then
+      if test $ac_qt_version_major -lt 6; then
+         AC_MSG_ERROR([lupdate $ac_errmsg (qt5-linguist)])
+      else
+         AC_MSG_ERROR([lupdate $ac_errmsg (qt6-linguist)])
+      fi
+   else
+      ac_lupdate=$ac_cv_lupdate;
+   fi
 fi
 AC_SUBST(ac_lupdate)
 
 # Check for Qt lrelease utility.
-AC_PATH_PROG(ac_lrelease, lrelease, [no], $ac_path)
-if test "x$ac_release" = "xno"; then
-   AC_MSG_ERROR([lrelease $ac_errmsg])
+AC_PATH_TOOL(ac_lrelease, lrelease, [no], $ac_path)
+if test "x$ac_lrelease" = "xno"; then
+   if test $ac_qt_version_major -lt 6; then
+      AC_PATH_TOOL(ac_cv_lrelease, lrelease-qt5, [no], $ac_path)
+   else
+      AC_PATH_TOOL(ac_cv_lrelease, lrelease-qt6, [no], $ac_path)
+   fi
+   if test "x$ac_cv_lrelease" = "xno"; then
+      if test $ac_qt_version_major -lt 6; then
+         AC_MSG_ERROR([lrelease $ac_errmsg (qt5-linguist)])
+      else
+         AC_MSG_ERROR([lrelease $ac_errmsg (qt6-linguist)])
+      fi
+   else
+      ac_lrelease=$ac_cv_lrelease;
+   fi
 fi
 AC_SUBST(ac_lrelease)
 
@@ -273,16 +363,23 @@
 fi
 
 # Check for mandatory libraries.
-AC_CHECK_LIB(lscp, main, [ac_liblscp="yes"], [ac_liblscp="no"])
-if test "x$ac_liblscp" = "xno"; then
-   AC_MSG_ERROR([LSCP library not found.])
+PKG_CHECK_MODULES([LSCP], [lscp], [ac_liblscp="yes"], [ac_liblscp="no"])
+if test "x$ac_liblscp" = "xyes"; then
+   AC_DEFINE(CONFIG_LIBLSCP, 1, [Define if liblscp is available.])
+   ac_cflags="$ac_cflags $LSCP_CFLAGS"
+   ac_libs="$ac_libs $LSCP_LIBS"
+   CFLAGS="$CFLAGS $LSCP_CFLAGS"
+   CPPFLAGS="$CPPFLAGS $LSCP_CFLAGS"
+   LIBS="$LIBS $LSCP_LIBS"
+else
+   AC_MSG_ERROR([*** LSCP library not found (liblscp).])
 fi
-ac_libs="$ac_libs -llscp"
+
 case "{$host}" in
-     *mingw*)
-     ac_libs="$ac_libs -lws2_32"
-     LIBS="$LIBS -lws2_32"
-     ;;
+   *mingw*)
+   ac_libs="$ac_libs -lws2_32"
+   LIBS="$LIBS -lws2_32"
+   ;;
 esac
 
 AC_CACHE_CHECK([for instrument_name in lscp_channel_info_t],
@@ -398,18 +495,26 @@
   AC_DEFINE(CONFIG_MAX_VOICES, 1, [Define if max. voices / streams is available.])
 fi
 
+AC_CHECK_LIB(lscp, lscp_client_connection_lost, [ac_lscp_conn_lost="yes"], [ac_lscp_conn_lost="no"])
+if test "x$ac_lscp_conn_lost" = "xyes"; then
+  AC_DEFINE(CONFIG_LSCP_CLIENT_CONNECTION_LOST, 1, [Define if liblscp function lscp_client_connection_lost() is available.])
+fi
+
 # Check for optional libraries.
 if test "x$ac_libgig" = "xyes"; then
-   PKG_CHECK_MODULES(LIBGIG, gig >= 3.3.0, [ac_libgig="yes"], [ac_libgig="no"])
-   if test "x$ac_libgig" = "xyes"; then
-      AC_DEFINE(CONFIG_LIBGIG, 1, [Define if libgig is available.])
-      AC_SUBST(LIBGIG_CFLAGS)
-      AC_SUBST(LIBGIG_LIBS)
-      ac_cflags="$ac_cflags $LIBGIG_CFLAGS"
-      ac_libs="$ac_libs $LIBGIG_LIBS"
-      AC_DEFINE(CONFIG_LIBGIG_SETAUTOLOAD, 1, [Define if libgig provides gig::File::SetAutoLoad() method.])
-      ac_libgig_setautoload="yes"
-   fi
+   PKG_CHECK_MODULES([GIG], [gig >= 3.3.0], [ac_libgig="yes"], [ac_libgig="no"])
+fi
+if test "x$ac_libgig" = "xyes"; then
+   AC_DEFINE(CONFIG_LIBGIG, 1, [Define if libgig is available.])
+   ac_cflags="$ac_cflags $GIG_CFLAGS"
+   ac_libs="$ac_libs $GIG_LIBS"
+   CFLAGS="$CFLAGS $GIG_CFLAGS"
+   CPPFLAGS="$CPPFLAGS $GIG_CFLAGS"
+   LIBS="$LIBS $GIG_LIBS"
+   AC_DEFINE(CONFIG_LIBGIG_SETAUTOLOAD, 1, [Define if libgig provides gig::File::SetAutoLoad() method.])
+   ac_libgig_setautoload="yes"
+else
+   AC_MSG_WARN([*** GIG library not found (libgig).])
 fi
 
 # Check for round math function.
@@ -418,31 +523,12 @@
    AC_DEFINE(CONFIG_ROUND, 1, [Define if round is available.])
 fi
 
-# Check for debugging stack-trace.
-if test "x$ac_stacktrace" = "xyes"; then
-   AC_DEFINE(CONFIG_STACKTRACE, 1, [Define if debugger stack-trace is enabled.])
-fi
-
-# Some recent distros (eg. fedora, debian) require this.
-if test "x$ac_cv_lib_X11_main" = "xyes"; then
-   ac_libs="$ac_libs -lX11"
-fi
-
-AC_SUBST(ac_libs)
-AC_SUBST(ac_incpath)
-AC_SUBST(ac_cflags)
-AC_SUBST(ac_ldflags)
 
 # Checks for header files.
 AC_HEADER_STDC
 AC_HEADER_SYS_WAIT
 AC_CHECK_HEADERS(fcntl.h sys/ioctl.h unistd.h signal.h sys/socket.h)
 
-AC_CHECK_HEADER(lscp/client.h, [ac_lscp_h="yes"], [ac_lscp_h="no"])
-if test "x$ac_lscp_h" = "xno"; then
-   AC_MSG_ERROR([LSCP headers not found.])
-fi
-
 if test "x$ac_libgig" = "xyes"; then
    AC_CHECK_HEADER(libgig/SF.h, [ac_libgig_sf2="yes"], [ac_libgig_sf2="no"])
    if test "x$ac_libgig_sf2" = "xyes"; then
@@ -450,6 +536,31 @@
    fi
 fi
 
+# Check for unique/single instance support.
+if test "x$ac_xunique" = "xyes"; then
+   if test $ac_qt_version_major -lt 6; then
+      PKG_CHECK_MODULES([QT5NETWORK], [Qt5Network], [ac_xunique="yes"], [ac_xunique="no"])
+   else
+      PKG_CHECK_MODULES([QT6NETWORK], [Qt6Network], [ac_xunique="yes"], [ac_xunique="no"])
+   fi
+fi
+if test "x$ac_xunique" = "xyes"; then
+   AC_DEFINE(CONFIG_XUNIQUE, 1, [Define if unique/single instance is enabled.])
+   ac_qnetwork="network"
+fi
+AC_SUBST(ac_qnetwork)
+
+# Check for debugging stack-trace.
+if test "x$ac_stacktrace" = "xyes"; then
+   AC_DEFINE(CONFIG_STACKTRACE, 1, [Define if debugger stack-trace is enabled.])
+fi
+
+AC_SUBST(ac_cflags)
+AC_SUBST(ac_ldflags)
+AC_SUBST(ac_incpath)
+AC_SUBST(ac_libs)
+
+
 # Checks for typedefs, structures, and compiler characteristics.
 # AC_C_CONST
 
@@ -464,7 +575,7 @@
 # Output summary message
 
 echo
-echo "  $PACKAGE_NAME $PACKAGE_VERSION"
+echo "  $PACKAGE_NAME $ac_build_version (Qt $ac_qt_version)"
 echo
 echo "  Build target . . . . . . . . . . . . . . . . . . .: $ac_debug"
 echo
@@ -485,7 +596,9 @@
 echo "  LSCP channel MIDI event support  . . . . . . . . .: $ac_channel_midi_event"
 echo "  LSCP device MIDI event support . . . . . . . . . .: $ac_device_midi_event"
 echo "  LSCP runtime max. voices / disk streams support  .: $ac_max_voices"
+echo "  LSCP connection loss support . . . . . . . . . . .: $ac_lscp_conn_lost"
 echo
+echo "  Unique/Single instance support . . . . . . . . . .: $ac_xunique"
 echo "  Debugger stack-trace (gdb) . . . . . . . . . . . .: $ac_stacktrace"
 echo
 echo "  Install prefix . . . . . . . . . . . . . . . . . .: $ac_prefix"