Allow the user to specify their own additional CFLAGS and LDFLAGS when

they run configure/autogen.sh.

If the environment variables CFLAGS and/or LDFLAGS are set, their values
are saved and appended to the values that are set in configure.in.

Example (csh-style, cope):

% setenv CFLAGS -D_REENTRANT
% ./autogen.sh


git-svn-id: http://svn.xiph.org/trunk/ao@1372 0101bb08-14d6-0310-b084-bc0e0c8e3800

configure.in

@@ -29,6 +29,8 @@ dnl ====================================
 dnl Set some general compile options
 dnl ====================================
 
+cflags_save="$CFLAGS"
+ldflags_save="$LDFLAGS"
 if test -z "$GCC"; then
         case $host in
         *-*-irix*)
@@ -64,6 +66,8 @@ else
                 PROFILE="-O20 -g -pg -D__NO_MATH_INLINES -fsigned-char" ;;
         esac
 fi
+CFLAGS="$CFLAGS $cflags_save"
+LDFLAGS="$LDFLAGS $ldflags_save"
 
 
 AC_SUBST(DEBUG)