Spring cleanup ...: - configure.in Makefile.am config.h.in

Spring cleanup ...:
- configure.in Makefile.am config.h.in xmlversion.h.in: detect if
  we need string functions
- trio.[ch] strio.[ch]: embedded the Trio-0.23 string functions
  to be able to use them where needed. Applied some changes
  to reduce name linking pollution and compile in only what's
  needed.
- HTMLtree.c debugXML.c entities.c error.c nanoftp.c valid.c
  xlink.c xmlversion.h.in xpath.c: got rid of the #ifdef
  for the string manipulation functions
- xmlmemory.[ch]: removed DEBUG_MEMORY_FREED and added it automatically
  to the free() function of xmlmemory.c
- entities.c HTMLtree.c parserInternals.c tree.c uri.c valid.c
  xinclude.c xmlIO.c xpath.c xpointer.c: removed the MEM_CLEANUP
  usage.
Daniel
diff --git a/configure.in b/configure.in
index 553a145..bac5847 100644
--- a/configure.in
+++ b/configure.in
@@ -100,11 +100,15 @@
 
 dnl Checks for library functions.
 AC_FUNC_STRFTIME
-AC_CHECK_FUNCS(strdup strndup strerror snprintf vsnprintf)
+AC_CHECK_FUNCS(strdup strndup strerror)
 AC_CHECK_FUNCS(finite isnand fp_class class fpclass)
 AC_CHECK_FUNCS(strftime localtime)
 AC_CHECK_FUNCS(stat _stat)
 
+dnl Checking the standard string functions availability
+AC_CHECK_FUNCS(printf sprintf fprintf snprintf vfprintf vsprintf vsnprintf sscanf,,
+               NEED_TRIO=1)
+
 dnl Checks for inet libraries:
 AC_CHECK_FUNC(gethostent, , AC_CHECK_LIB(nsl, gethostent))
 AC_CHECK_FUNC(setsockopt, , AC_CHECK_LIB(socket, setsockopt))
@@ -240,6 +244,19 @@
     CFLAGS="-Wall -g -O -pedantic -W -Wunused -Wimplicit -Wreturn-type -Wswitch -Wcomment -Wtrigraphs -Wformat -Wchar-subscripts -Wuninitialized -Wparentheses -Wshadow -Wpointer-arith -Wcast-align -Wwrite-strings -Waggregate-return -Wstrict-prototypes -Wmissing-prototypes -Wnested-externs -Winline "
 dnl -Wcast-qual -ansi
 fi
+
+dnl
+dnl Check for trio string functions
+dnl
+
+if test "${NEED_TRIO}" = "1" ; then
+    echo Adding trio library for string functions
+    WITH_TRIO=1
+else    
+    WITH_TRIO=0
+fi
+AC_SUBST(WITH_TRIO)
+
 dnl
 dnl Aloow to disable various pieces
 dnl