Do an autoreconf -ivf

This was done on a Ubuntu 14.04 system with wxWidgets 3.1.1 installed.
The resulting buildfiles successfully build Audacity on Ubuntu 14.04 (with 3.1.1) and on Travis (with 3.0.0).

configure

@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for audacity 2.2.2.
+# Generated by GNU Autoconf 2.69 for audacity 2.3.0.
 #
 #
 # Copyright (C) 1992-1996, 1998-2012 Free Software Foundation, Inc.
@@ -587,8 +587,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='audacity'
 PACKAGE_TARNAME='audacity'
-PACKAGE_VERSION='2.2.2'
-PACKAGE_STRING='audacity 2.2.2'
+PACKAGE_VERSION='2.3.0'
+PACKAGE_STRING='audacity 2.3.0'
 PACKAGE_BUGREPORT=''
 PACKAGE_URL=''
 
@@ -1585,7 +1585,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures audacity 2.2.2 to adapt to many kinds of systems.
+\`configure' configures audacity 2.3.0 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1655,7 +1655,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of audacity 2.2.2:";;
+     short | recursive ) echo "Configuration of audacity 2.3.0:";;
    esac
   cat <<\_ACEOF
 
@@ -1710,7 +1710,7 @@ Optional Packages:
                         (or the compiler's sysroot if not specified).
   --with-lib-preference   whether to use local and/or system libraries, in
                           order of preference (default="system local")
-  --with-wx-version       select wxWidgets version (if both installed) [3.0,]
+  --with-wx-version       select wxWidgets version (if both installed) [3.1,]
   --with-expat            which expat to use for XML file support:
                           [system,local]
   --with-ffmpeg           use ffmpeg for import and export support
@@ -1881,7 +1881,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-audacity configure 2.2.2
+audacity configure 2.3.0
 generated by GNU Autoconf 2.69
 
 Copyright (C) 2012 Free Software Foundation, Inc.
@@ -2519,7 +2519,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by audacity $as_me 2.2.2, which was
+It was created by audacity $as_me 2.3.0, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   $ $0 $@
@@ -3388,7 +3388,7 @@ fi
 
 # Define the identity of the package.
  PACKAGE='audacity'
- VERSION='2.2.2'
+ VERSION='2.3.0'
 
 
 cat >>confdefs.h <<_ACEOF
@@ -19834,7 +19834,7 @@ _ACEOF
 
 
 
-for ac_prog in $WX_CONFIG wx-config wx-config-3.0
+for ac_prog in $WX_CONFIG wx-config wx-config-3.1
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -19894,16 +19894,17 @@ fi
 wxconfigargs="$static_wx_preference $unicode_preference $wxconfigargs $wx_preference"
 wx_version=`${WX_CONFIG} $wxconfigargs --version`
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: Checking that the chosen version of wxWidgets is 3.0.x" >&5
-$as_echo "$as_me: Checking that the chosen version of wxWidgets is 3.0.x" >&6;}
+{ $as_echo "$as_me:${as_lineno-$LINENO}: Checking that the chosen version of wxWidgets is 3.1.x (or 3.0.x)" >&5
+$as_echo "$as_me: Checking that the chosen version of wxWidgets is 3.1.x (or 3.0.x)" >&6;}
 
 case "${wx_version}" in
-  3.0.*)
+  3.1.* | 3.0.*)
     echo "Great, you're using wxWidgets ${wx_version}!"
     ;;
   *)
   wx_list=`${WX_CONFIG} --list`
-  as_fn_error $? "Unable to locate a suitable configuration of wxWidgets v3.0.x or higher.
+  as_fn_error $? "Unable to locate a suitable configuration of wxWidgets v3.1.x
+or higher (or even of 3.0.x).  We recommend building with 3.1.x.
 The currently available configurations are listed below.  If necessary, either
 install the package for your distribution or download the latest version of
 wxWidgets
@@ -24930,7 +24931,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by audacity $as_me 2.2.2, which was
+This file was extended by audacity $as_me 2.3.0, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -24996,7 +24997,7 @@ _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
 ac_cs_version="\\
-audacity config.status 2.2.2
+audacity config.status 2.3.0
 configured by $0, generated by GNU Autoconf 2.69,
   with options \\"\$ac_cs_config\\"