Remove redundant check for libao which causes it to always be required even if
mp3 and ogg support are disabled.

--- configure.ac.orig	2023-02-03 14:46:06 UTC
+++ configure.ac
@@ -314,8 +314,10 @@ dnl Check for libao
 esac
 
 dnl Check for libao
+if test "$with_mp3_support" = yes || test "$with_ogg_support" = yes || test "$en_gcdmaster" = yes; then
 PKG_CHECK_MODULES(AO, ao >= 0.8, [AC_DEFINE(HAVE_AO,1,"")],
         [echo "gcdmaster, MP3 and Ogg support disabled"; en_gcdmaster=no; with_ogg_support=no; with_mp3_support=no])
+fi
 
 dnl Check for OGG support
 if test "$with_ogg_support" = yes; then
@@ -339,12 +341,6 @@ if test "$with_mp3_support" = yes; then
 	                echo "MP3 support disabled"; with_mp3_support=no
 		fi
 	fi
-fi
-
-dnl Check for libao support
-if test "$with_mp3_support" = yes || test "$with_ogg_support" = yes || test "$en_gcdmaster" = yes; then
-PKG_CHECK_MODULES(AO, ao >= 0.8, [AC_DEFINE(HAVE_AO,1,"")],
-        [echo "Building of gcdmaster disabled"; en_gcdmaster=no])
 fi
 
 if test "$with_ogg_support" = yes; then