diff --git a/acinclude.m4.in b/acinclude.m4.in
index 13d12b7..a82b560 100644
--- a/acinclude.m4.in
+++ b/acinclude.m4.in
@@ -331,6 +331,18 @@ AC_DEFUN([AC_PATH_QT_MOC_UIC],
              UIC="$UIC -nounload"
          fi
        fi
+
+       if test $kde_qtver = 4; then
+         KDE_CHECK_UIC_FLAG(L,[/nonexistent],ac_uic_supports_libpath=yes,ac_uic_supports_libpath=no)
+         KDE_CHECK_UIC_FLAG(nounload,,ac_uic_supports_nounload=yes,ac_uic_supports_nounload=no)
+
+         if test x$ac_uic_supports_libpath = xyes; then
+             UIC="$UIC -L \$(kde_widgetdir)"
+         fi
+         if test x$ac_uic_supports_nounload = xyes; then
+             UIC="$UIC -nounload"
+         fi
+       fi
      fi
    else
      UIC="echo uic not available: "
@@ -343,6 +355,9 @@ AC_DEFUN([AC_PATH_QT_MOC_UIC],
    if test $kde_qtver = 3; then
      UIC_TR="tr2i18n"
    fi
+   if test $kde_qtver = 4; then
+     UIC_TR="tr2i18n"
+   fi
 
    AC_SUBST(UIC_TR)
 ])
@@ -599,6 +614,10 @@ AC_DEFUN([KDE_SUBST_PROGRAMS],
                 fi
               fi
             fi
+            if test "$kde_qtver" = "4"; then
+              kde32ornewer=
+              kde33ornewer=
+            fi
         fi
 
         if test -n "$kde32ornewer"; then
@@ -1092,9 +1111,22 @@ AC_DEFUN([KDE_PRINT_QT_PROGRAM],
 AC_REQUIRE([KDE_USE_QT])
 cat > conftest.$ac_ext <<EOF
 #include "confdefs.h"
+EOF
+
+if test "$kde_qtver" = "4"; then
+cat >> conftest.$ac_ext <<EOF
+#include <Qt/qglobal.h>
+#include <Qt/qapplication.h>
+EOF
+fi
+
+if test "$kde_qtver" = "3"; then
+cat >> conftest.$ac_ext <<EOF
 #include <qglobal.h>
 #include <qapplication.h>
 EOF
+fi
+
 if test "$kde_qtver" = "2"; then
 cat >> conftest.$ac_ext <<EOF
 #include <qevent.h>
@@ -1119,6 +1151,13 @@ cat >> conftest.$ac_ext <<EOF
 EOF
 fi
 
+if test "$kde_qtver" = "4"; then
+cat >> conftest.$ac_ext <<EOF
+#include <Qt/qcursor.h>
+#include <Qt/qstylefactory.h>
+EOF
+fi
+
 echo "#if ! ($kde_qt_verstring)" >> conftest.$ac_ext
 cat >> conftest.$ac_ext <<EOF
 #error 1
@@ -1144,6 +1183,12 @@ cat >> conftest.$ac_ext <<EOF
     QCursor c(Qt::WhatsThisCursor);
 EOF
 fi
+if test "$kde_qtver" = "4"; then
+cat >> conftest.$ac_ext <<EOF
+    (void)QStyleFactory::create(QString::null);
+    QCursor c(Qt::WhatsThisCursor);
+EOF
+fi
 cat >> conftest.$ac_ext <<EOF
     return 0;
 }
@@ -1191,6 +1236,21 @@ if test -z "$2"; then
       kde_qt_minversion=">= Qt 3.0 and < 4.0"
     fi
   fi
+  if test "$kde_qtver" = "4"; then
+    if test $kde_qtsubver -gt 0; then
+	 if test $kde_qtsubver -gt 1; then
+	    if test $kde_qtsubver -gt 2; then
+		kde_qt_minversion=">= Qt 4.3 and < 5.0"
+	    else
+	        kde_qt_minversion=">= Qt 4.2 and < 5.0"
+	    fi
+	 else
+            kde_qt_minversion=">= Qt 4.1 and < 5.0"
+         fi
+    else
+      kde_qt_minversion=">= Qt 4.0 and < 5.0"
+    fi
+  fi
   if test "$kde_qtver" = "1"; then
     kde_qt_minversion=">= 1.42 and < 2.0"
   fi
@@ -1199,6 +1259,15 @@ else
 fi
 
 if test -z "$3"; then
+   if test $kde_qtver = 4; then
+     if test $kde_qtsubver -gt 0; then
+       kde_qt_verstring="QT_VERSION >= 0x04@VER@00 && QT_VERSION < 0x050000"
+       qtsubver=`echo "00$kde_qtsubver" | sed -e 's,.*\(..\)$,\1,'`
+       kde_qt_verstring=`echo $kde_qt_verstring | sed -e "s,@VER@,$qtsubver,"`
+     else
+       kde_qt_verstring="QT_VERSION >= 400 && QT_VERSION < 0x050000"
+     fi
+   fi
    if test $kde_qtver = 3; then
      if test $kde_qtsubver -gt 0; then
        kde_qt_verstring="QT_VERSION >= 0x03@VER@00 && QT_VERSION < 0x040000"
@@ -1357,20 +1426,31 @@ dnl ------------------------------------------------------------------------
 dnl If we haven't been told how to link to Qt, we work it out for ourselves.
 dnl ------------------------------------------------------------------------
 if test -z "$LIBQT_GLOB"; then
-  if test "x$kde_use_qt_emb" = "xyes"; then
-    LIBQT_GLOB="libqte.*"
-  else
-    LIBQT_GLOB="libqt.*"
+  if test "$kde_qtver" = "4"; then
+    LIBQT_GLOB="libQtCore.*"
+  fi
+  if test "$kde_qtver" = "3"; then
+    if test "x$kde_use_qt_emb" = "xyes"; then
+      LIBQT_GLOB="libqte.*"
+    else
+      LIBQT_GLOB="libqt.*"
+    fi
   fi
 fi
 
 dnl ------------------------------------------------------------
 dnl If we got --enable-embedded then adjust the Qt library name.
+dnl Also Qt4 uses a different library name
 dnl ------------------------------------------------------------
-if test "x$kde_use_qt_emb" = "xyes"; then
-  qtlib="qte"
-else
-  qtlib="qt"
+if test "$kde_qtver" = "4"; then
+  qtlib="QtCore -lQtGui"
+fi
+if test "$kde_qtver" = "3"; then
+  if test "x$kde_use_qt_emb" = "xyes"; then
+    qtlib="qte"
+  else
+    qtlib="qt"
+  fi
 fi
 
 kde_int_qt="-l$qtlib"
@@ -1397,7 +1477,9 @@ dnl ------------------------------------------------------------------------
 if test "x$kde_use_qt_mt" = "xyes"; then
   LIBQT="-l$qtlib-mt"
   kde_int_qt="-l$qtlib-mt"
-  LIBQT_GLOB="lib$qtlib-mt.*"
+  if test "$kde_qtver" = "3"; then
+    LIBQT_GLOB="lib$qtlib-mt.*"
+  fi
   USING_QT_MT="using -mt"
 else
   LIBQT="-l$qtlib"
@@ -1415,6 +1497,11 @@ if test $kde_qtver = 3; then
   LIBQT="$LIBQT $LIBDL"
 fi
 
+if test $kde_qtver = 4; then
+  AC_REQUIRE([KDE_CHECK_LIBDL])
+  LIBQT="$LIBQT $LIBDL"
+fi
+
 AC_MSG_CHECKING([for Qt])
 
 if test "x$kde_use_qt_emb" != "xyes" && test "x$kde_use_qt_mac" != "xyes"; then
@@ -1465,7 +1552,11 @@ if test ! "$ac_qt_includes" = "NO"; then
 fi
 
 if test "$kde_qtver" != "1"; then
-  kde_qt_header=qstyle.h
+  if test "$kde_qtver" = "4"; then
+    kde_qt_header="Qt/qstyle.h"
+  else
+    kde_qt_header=qstyle.h
+  fi
 else
   kde_qt_header=qglobal.h
 fi
@@ -1598,6 +1689,8 @@ AC_SUBST(QT_INCLUDES)
 AC_SUBST(QT_LDFLAGS)
 AC_PATH_QT_MOC_UIC
 
+KDE_CHECK_TQT
+
 KDE_CHECK_QT_JPEG
 
 if test "x$kde_use_qt_emb" != "xyes" && test "x$kde_use_qt_mac" != "xyes"; then
@@ -2057,6 +2150,7 @@ AC_CACHE_VAL(kde_cv_have_kdeqtaddon,
  CXXFLAGS="$CXXFLAGS -I$prefix/include -I$prefix/include/kde $all_includes"
  LDFLAGS="$LDFLAGS $all_libraries $USER_LDFLAGS"
 
+if test "$kde_qtver" = "3"; then
  AC_TRY_LINK([
    #include <qdom.h>
  ],
@@ -2066,11 +2160,24 @@ AC_CACHE_VAL(kde_cv_have_kdeqtaddon,
   kde_cv_have_kdeqtaddon=yes,
   kde_cv_have_kdeqtaddon=no
  )
+fi
+
+if test "$kde_qtver" = "4"; then
+ AC_TRY_LINK([
+   #include <Qt/qdom.h>
+ ],
+ [
+   QDomDocument doc;
+ ],
+  kde_cv_have_kdeqtaddon=yes,
+  kde_cv_have_kdeqtaddon=no
+ )
 
  LDFLAGS=$kde_ldflags_safe
  LIBS=$kde_libs_safe
  CXXFLAGS=$kde_cxxflags_safe
 ])
+fi
 
 AC_MSG_RESULT($kde_cv_have_kdeqtaddon)
 
@@ -2086,7 +2193,33 @@ AC_DEFUN([KDE_CREATE_LIBS_ALIASES],
    AC_REQUIRE([KDE_CHECK_LIBDL])
    AC_REQUIRE([K_PATH_X])
 
-if test $kde_qtver = 3; then
+if test $kde_qtver = 4; then
+   case $host in 
+               *cygwin*) lib_kded="-lkdeinit_kded" ;;
+               *) lib_kded="" ;;
+       esac
+   AC_SUBST(LIB_KDED, $lib_kded)
+   AC_SUBST(LIB_KDECORE, "-lkdecore")
+   AC_SUBST(LIB_KDEUI, "-lkdeui")
+   AC_SUBST(LIB_KIO, "-lkio")
+   AC_SUBST(LIB_KJS, "-lkjs")
+   AC_SUBST(LIB_SMB, "-lsmb")
+   AC_SUBST(LIB_KAB, "-lkab")
+   AC_SUBST(LIB_KABC, "-lkabc")
+   AC_SUBST(LIB_KHTML, "-lkhtml")
+   AC_SUBST(LIB_KSPELL, "-lkspell")
+   AC_SUBST(LIB_KPARTS, "-lkparts")
+   AC_SUBST(LIB_KDEPRINT, "-lkdeprint")
+   AC_SUBST(LIB_KUTILS, "-lkutils")
+   AC_SUBST(LIB_KDEPIM, "-lkdepim")
+   AC_SUBST(LIB_KIMPROXY, "-lkimproxy")
+   AC_SUBST(LIB_KNEWSTUFF, "-lknewstuff")
+   AC_SUBST(LIB_KDNSSD, "-lkdnssd")
+   AC_SUBST(LIB_KUNITTEST, "-lkunittest")
+# these are for backward compatibility
+   AC_SUBST(LIB_KSYCOCA, "-lkio")
+   AC_SUBST(LIB_KFILE, "-lkio")
+elif test $kde_qtver = 3; then
    case $host in 
                *cygwin*) lib_kded="-lkdeinit_kded" ;;
                *) lib_kded="" ;;
@@ -2605,6 +2738,43 @@ AH_VERBATIM(_AC_CHECK_JPEG,
 ])
 ])
 
+AC_DEFUN([KDE_CHECK_TQT],
+[
+AC_MSG_CHECKING([if TQt is available])
+AC_CACHE_VAL(kde_cv_tqt,
+[
+AC_LANG_SAVE
+AC_LANG_CPLUSPLUS
+ac_save_LIBS="$LIBS"
+LIBS="$all_libraries $USER_LDFLAGS $LIBQT -ltqt"
+ac_save_CXXFLAGS="$CXXFLAGS"
+CXXFLAGS="$CXXFLAGS $all_includes $USER_INCLUDES"
+if test "$kde_qtver" -gt "2"; then
+AC_TRY_LINK(
+[#include <tqtimer.h>],
+            [
+            QTimer *test_timer(0);
+            test_timer->start(1000);],
+            eval "kde_cv_tqt=no",
+            eval "kde_cv_tqt=yes")
+fi
+LIBS="$ac_save_LIBS"
+CXXFLAGS="$ac_save_CXXFLAGS"
+AC_LANG_RESTORE
+])
+
+if eval "test ! \"`echo $kde_cv_tqt`\" = no"; then
+  AC_MSG_RESULT(no)
+dnl  AC_MSG_ERROR([You are attempting to compile Trinity without the Trinity Qt Interface installed.  Please install libtqtinterface-dev and try again!])
+else
+  AC_MSG_RESULT(yes)
+  LIBTQT_LDFLAGS="-ltqt"
+  all_libraries="$all_libraries $LIBTQT_LDFLAGS"
+  QT_LDFLAGS="$QT_LDFLAGS $LIBTQT_LDFLAGS"
+fi
+
+])
+
 AC_DEFUN([KDE_CHECK_QT_JPEG],
 [
 if test -n "$LIBJPEG"; then
@@ -2618,6 +2788,17 @@ LIBS="$all_libraries $USER_LDFLAGS $LIBQT"
 LIBS=`echo $LIBS | sed "s/$LIBJPEG//"`
 ac_save_CXXFLAGS="$CXXFLAGS"
 CXXFLAGS="$CXXFLAGS $all_includes $USER_INCLUDES"
+if test "$kde_qtver" = "4"; then
+AC_TRY_LINK(
+[#include <Qt/qapplication.h>],
+            [
+            int argc;
+            char** argv;
+            QApplication app(argc, argv);],
+            eval "kde_cv_qt_jpeg=no",
+            eval "kde_cv_qt_jpeg=yes")
+fi
+if test "$kde_qtver" = "3"; then
 AC_TRY_LINK(
 [#include <qapplication.h>],
             [
@@ -2626,6 +2807,7 @@ AC_TRY_LINK(
             QApplication app(argc, argv);],
             eval "kde_cv_qt_jpeg=no",
             eval "kde_cv_qt_jpeg=yes")
+fi
 LIBS="$ac_save_LIBS"
 CXXFLAGS="$ac_save_CXXFLAGS"
 AC_LANG_RESTORE
@@ -3462,6 +3644,7 @@ AC_DEFUN([KDE_ENABLE_HIDDEN_VISIBILITY],
           safe_CXXFLAGS=$CXXFLAGS
           CXXFLAGS="$CXXFLAGS $all_includes"
 
+if test "$kde_qtver" = "3"; then
           AC_TRY_COMPILE(
           [
 #include <qglobal.h>
@@ -3471,6 +3654,19 @@ AC_DEFUN([KDE_ENABLE_HIDDEN_VISIBILITY],
 #endif
           ], [/* elvis is alive */],
           kde_cv_val_qt_gcc_visibility_patched=no, kde_cv_val_qt_gcc_visibility_patched=yes)
+fi
+
+if test "$kde_qtver" = "4"; then
+AC_TRY_COMPILE(
+          [
+#include <Qt/qglobal.h>
+#if Q_EXPORT - 0 != 0
+/* if this compiles, then Q_EXPORT is undefined */
+/* if Q_EXPORT is nonempty, this will break compilation */
+#endif
+          ], [/* elvis is alive */],
+          kde_cv_val_qt_gcc_visibility_patched=no, kde_cv_val_qt_gcc_visibility_patched=yes)
+fi
 
           CXXFLAGS=$safe_CXXFLAGS
           AC_LANG_RESTORE
@@ -4712,6 +4908,8 @@ AC_LANG_SAVE
 AC_LANG_CPLUSPLUS
 ac_save_LIBS="$LIBS"
 ac_save_CXXFLAGS="$CXXFLAGS"
+
+if test "$kde_qtver" = "3"; then
 LIBS="$all_libraries -lqimgio -lpng -lz $LIBJPEG $LIBQT"
 CXXFLAGS="$CXXFLAGS -I$qt_incdir $all_includes"
 AC_TRY_RUN(dnl
@@ -4727,6 +4925,26 @@ int main() {
             ac_cv_lib_qimgio=yes,
             ac_cv_lib_qimgio=no,
 	    ac_cv_lib_qimgio=no)
+fi
+
+if test "$kde_qtver" = "4"; then
+LIBS="$all_libraries -lpng -lz $LIBJPEG $LIBQT"
+CXXFLAGS="$CXXFLAGS -I$qt_incdir $all_includes"
+AC_TRY_RUN(dnl
+[
+#include <tqimageio.h>
+#include <tqstring.h>
+int main() {
+		QString t = "hallo";
+		t.fill('t');
+		qInitImageIO();
+}
+],
+            ac_cv_lib_qimgio=yes,
+            ac_cv_lib_qimgio=no,
+	    ac_cv_lib_qimgio=no)
+fi
+
 LIBS="$ac_save_LIBS"
 CXXFLAGS="$ac_save_CXXFLAGS"
 AC_LANG_RESTORE