diff --git a/wxwin.m4 b/wxwin.m4
index f8e5b704a2..3e483c6e10 100644
--- a/wxwin.m4
+++ b/wxwin.m4
@@ -519,7 +519,7 @@ AC_DEFUN([WX_ARG_ENABLE_YESNOAUTO],
                 $2=0
             elif test "$enableval" = "auto" ; then
                 AC_MSG_RESULT([will be automatically detected])
-                $2="auto"
+                $2=""
             else
                 AC_MSG_ERROR([
     Unrecognized option value (allowed values: yes, no, auto)
@@ -545,7 +545,7 @@ AC_DEFUN([WX_ARG_WITH_YESNOAUTO],
                 $2=0
             elif test "$withval" = "auto" ; then
                 AC_MSG_RESULT([will be automatically detected])
-                $2="auto"
+                $2=""
             else
                 AC_MSG_ERROR([
     Unrecognized option value (allowed values: yes, auto)
@@ -597,17 +597,17 @@ AC_DEFUN([WX_STANDARD_OPTIONS],
                 AC_MSG_CHECKING([for the --with-toolkit option])
                 if test "$withval" = "auto" ; then
                     AC_MSG_RESULT([will be automatically detected])
-                    TOOLKIT="auto"
+                    TOOLKIT=""
                 else
                     TOOLKIT="$withval"
 
                     dnl PORT must be one of the allowed values
-                    if test "$TOOLKIT" != "gtk1" -a "$TOOLKIT" != "gtk2" -a \
+                    if test "$TOOLKIT" != "gtk1" -a "$TOOLKIT" != "gtk2" -a "$TOOLKIT" != "gtk3" -a \
                             "$TOOLKIT" != "msw" -a "$TOOLKIT" != "motif" -a \
                             "$TOOLKIT" != "osx_carbon" -a "$TOOLKIT" != "osx_cocoa" -a \
                             "$TOOLKIT" != "dfb" -a "$TOOLKIT" != "x11"; then
                         AC_MSG_ERROR([
-    Unrecognized option value (allowed values: auto, gtk1, gtk2, msw, motif, osx_carbon, osx_cocoa, dfb, x11)
+    Unrecognized option value (allowed values: auto, gtk1, gtk2, gtk3, msw, motif, osx_carbon, osx_cocoa, dfb, x11)
                         ])
                     fi
 
@@ -671,7 +671,7 @@ AC_DEFUN([WX_STANDARD_OPTIONS],
                 AC_MSG_CHECKING([for the --with-wxversion option])
                 if test "$withval" = "auto" ; then
                     AC_MSG_RESULT([will be automatically detected])
-                    WX_RELEASE="auto"
+                    WX_RELEASE=""
                 else
 
                     wx_requested_major_version=`echo $withval | \
@@ -706,7 +706,7 @@ dnl ---------------------------------------------------------------------------
 dnl WX_CONVERT_STANDARD_OPTIONS_TO_WXCONFIG_FLAGS
 dnl
 dnl Sets the WXCONFIG_FLAGS string using the SHARED,DEBUG,UNICODE variable values
-dnl which are different from "auto".
+dnl which were specified.
 dnl Thus this macro needs to be called only once all options have been set.
 dnl ---------------------------------------------------------------------------
 AC_DEFUN([WX_CONVERT_STANDARD_OPTIONS_TO_WXCONFIG_FLAGS],
@@ -730,11 +730,11 @@ AC_DEFUN([WX_CONVERT_STANDARD_OPTIONS_TO_WXCONFIG_FLAGS],
             WXCONFIG_FLAGS="$WXCONFIG_FLAGS""--unicode=no "
         fi
 
-        if test "$TOOLKIT" != "auto" ; then
+        if test -n "$TOOLKIT" ; then
             WXCONFIG_FLAGS="$WXCONFIG_FLAGS""--toolkit=$TOOLKIT "
         fi
 
-        if test "$WX_RELEASE" != "auto" ; then
+        if test -n "$WX_RELEASE" ; then
             WXCONFIG_FLAGS="$WXCONFIG_FLAGS""--version=$WX_RELEASE "
         fi
 
@@ -748,16 +748,16 @@ AC_DEFUN([WX_CONVERT_STANDARD_OPTIONS_TO_WXCONFIG_FLAGS],
 
 
 dnl ---------------------------------------------------------------------------
-dnl _WX_SELECTEDCONFIG_CHECKFOR([RESULTVAR], [STRING], [MSG]
-dnl                             [, ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND]])
+dnl _WX_SELECTEDCONFIG_CHECKFOR([RESULTVAR], [STRING], [MSG])
 dnl
-dnl Outputs the given MSG. Then searches the given STRING in the wxWidgets
-dnl additional CPP flags and put the result of the search in WX_$RESULTVAR
-dnl also adding the "yes" or "no" message result to MSG.
+dnl Sets WX_$RESULTVAR to the value of $RESULTVAR if it's defined. Otherwise,
+dnl auto-detect the value by checking for the presence of STRING in
+dnl $WX_SELECTEDCONFIG (which is supposed to be set by caller) and set
+dnl WX_$RESULTVAR to either 0 or 1, also outputting "yes" or "no" after MSG.
 dnl ---------------------------------------------------------------------------
 AC_DEFUN([_WX_SELECTEDCONFIG_CHECKFOR],
         [
-        if test "$$1" = "auto" ; then
+        if test -z "$$1" ; then
 
             dnl The user does not have particular preferences for this option;
             dnl so we will detect the wxWidgets relative build setting and use it
@@ -772,11 +772,9 @@ AC_DEFUN([_WX_SELECTEDCONFIG_CHECKFOR],
             if test "$WX_$1" != "0"; then
                 WX_$1=1
                 AC_MSG_RESULT([yes])
-                ifelse([$4], , :, [$4])
             else
                 WX_$1=0
                 AC_MSG_RESULT([no])
-                ifelse([$5], , :, [$5])
             fi
         else
 
@@ -823,19 +821,16 @@ AC_DEFUN([WX_DETECT_STANDARD_OPTION_VALUES],
             echo "[[dbg]] WX_SELECTEDCONFIG: $WX_SELECTEDCONFIG"
         fi
 
-
         dnl we could test directly for WX_SHARED with a line like:
         dnl    _WX_SELECTEDCONFIG_CHECKFOR([SHARED], [shared],
         dnl                                [if wxWidgets was built in SHARED mode])
         dnl but wx-config --selected-config DOES NOT outputs the 'shared'
         dnl word when wx was built in shared mode; it rather outputs the
         dnl 'static' word when built in static mode.
-        if test $WX_SHARED = "1"; then
+        if test "$WX_SHARED" = "1"; then
             STATIC=0
-        elif test $WX_SHARED = "0"; then
+        elif test "$WX_SHARED" = "0"; then
             STATIC=1
-        elif test $WX_SHARED = "auto"; then
-            STATIC="auto"
         fi
 
         dnl Now set the WX_UNICODE, WX_DEBUG, WX_STATIC variables
@@ -858,7 +853,7 @@ AC_DEFUN([WX_DETECT_STANDARD_OPTION_VALUES],
         AC_SUBST(WX_SHARED)
 
         dnl detect the WX_PORT to use
-        if test "$TOOLKIT" = "auto" ; then
+        if test -z "$TOOLKIT" ; then
 
             dnl The user does not have particular preferences for this option;
             dnl so we will detect the wxWidgets relative build setting and use it
@@ -866,6 +861,7 @@ AC_DEFUN([WX_DETECT_STANDARD_OPTION_VALUES],
 
             WX_GTKPORT1=$(expr "$WX_SELECTEDCONFIG" : ".*gtk1.*")
             WX_GTKPORT2=$(expr "$WX_SELECTEDCONFIG" : ".*gtk2.*")
+            WX_GTKPORT3=$(expr "$WX_SELECTEDCONFIG" : ".*gtk3.*")
             WX_MSWPORT=$(expr "$WX_SELECTEDCONFIG" : ".*msw.*")
             WX_MOTIFPORT=$(expr "$WX_SELECTEDCONFIG" : ".*motif.*")
             WX_OSXCOCOAPORT=$(expr "$WX_SELECTEDCONFIG" : ".*osx_cocoa.*")
@@ -876,6 +872,7 @@ AC_DEFUN([WX_DETECT_STANDARD_OPTION_VALUES],
             WX_PORT="unknown"
             if test "$WX_GTKPORT1" != "0"; then WX_PORT="gtk1"; fi
             if test "$WX_GTKPORT2" != "0"; then WX_PORT="gtk2"; fi
+            if test "$WX_GTKPORT3" != "0"; then WX_PORT="gtk3"; fi
             if test "$WX_MSWPORT" != "0"; then WX_PORT="msw"; fi
             if test "$WX_MOTIFPORT" != "0"; then WX_PORT="motif"; fi
             if test "$WX_OSXCOCOAPORT" != "0"; then WX_PORT="osx_cocoa"; fi
@@ -899,14 +896,8 @@ AC_DEFUN([WX_DETECT_STANDARD_OPTION_VALUES],
 
             AC_MSG_RESULT([$WX_PORT])
         else
-
             dnl Use the setting given by the user
-            if test -z "$TOOLKIT" ; then
-                WX_PORT=$TOOLKIT
-            else
-                dnl try with PORT
-                WX_PORT=$PORT
-            fi
+            WX_PORT=$TOOLKIT
         fi
 
         AC_SUBST(WX_PORT)
@@ -938,17 +929,17 @@ AC_DEFUN([WX_DETECT_STANDARD_OPTION_VALUES],
         fi
 
         dnl now we can finally update the DEBUG,UNICODE,SHARED options
-        dnl to their final values if they were set to 'auto'
-        if test "$DEBUG" = "auto"; then
+        dnl to their final values if they were not already set
+        if test -z "$DEBUG" ; then
             DEBUG=$WX_DEBUG
         fi
-        if test "$UNICODE" = "auto"; then
+        if test -z "$UNICODE" ; then
             UNICODE=$WX_UNICODE
         fi
-        if test "$SHARED" = "auto"; then
+        if test -z "$SHARED" ; then
             SHARED=$WX_SHARED
         fi
-        if test "$TOOLKIT" = "auto"; then
+        if test -z "$TOOLKIT" ; then
             TOOLKIT=$WX_PORT
         fi