Lpc2000

Hi,
I have a problem with including the stdio.h into my project in 
Hitop5 for programming a LPC controller.
Hitop5 is the programming IDE from Hitex and uses the GNU compiler.
I need the the libary because of the sprintf command.
The libary is included with:
#include <stdio.h>
and the syntax of the sprintf command is 100% correct.
So there must be a problem with the including or the use of libary 
header files.
Here for example some warnings from the built process:
********************************************************
(C:\Programme\Hitex\GnuToolPackageArm\arm-hitex-elarm-hitex-elf-ld: 
Warning: C:\Programme\Hitex\GnuToolPackageArm\arm-hitex-
elf\lib/libc.a(sprintf.o) does not support interworking, 
whereas .\objects\2138LCD.elf does
arm-hitex-elf-ld: Warning: C:\Programme\Hitex\GnuToolPackageArm\arm-
hitex-elf\lib/libc.a(vfprintf.o) does not support interworking, 
whereas .\objects\2138LCD.elf does
...

C:\Programme\Hitex\GnuToolPackageArm\arm-hitex-elf\lib/libc.a
(vfprintf.o)(.text+0xb54): In function `_vfprintf_r':
../../../../../../GccSources/newlib-
1.13.0/newlib/libc/stdio/vfprintf.c:821: undefined reference to 
`__ltdf2'
...

C:\Programme\Hitex\GnuToolPackageArm\arm-hitex-elf\lib/libc.a
(mprec.o)(.text+0xbdc): In function `_mprec_log10':
../../../../../../GccSources/newlib-
1.13.0/newlib/libc/stdlib/mprec.c:983: undefined reference to 
`__muldf3'
...
**************************************************************
There are a lot more similar warnings or errors like above.

Has anyone an idea or can help? Or is anyone working with Hitop 5 
and doesn't have this problem with including libary files?

It would also be helpful,if there are functions which can change 
integers or floats into char(in decimal, hex and binary syntax)
Thanks for helping
Bye Bye
Gerald