String array in ROM gives error in spite of following example code.

Hi,

I recently updated WinAVR to a newer version of the AVR-GCC toolchain,
downloaded from the Atmel site.

My version is this:

avr-gcc (AVR_8_bit_GNU_Toolchain_3.4.3_1072) 4.8.1

My code was compiling without errors before, but with this version, it
is giving errors in spite of following the instructions in the faq
section of the avr-libc document.
//---------------------------------------------
#include <avr/io.h>
#include <avr/pgmspace.h>

const char ptmpUP_msg[]      PROGMEM = "Upper Temp" ;
const char ptmpDN_msg[]      PROGMEM = "Lower Temp" ;
const char ptmpCLG_msg[]     PROGMEM = "Chiller Temp" ;

PGM_P  pgtmp_msg[]    PROGMEM =
   { ptmpUP_msg, ptmpDN_msg,  ptmpCLG_msg,} ;

//------------------------------------------------------
The above code gives the following error:

error: variable 'pgtmp_msg' must be const in order to be put into
read-only section by means of  '__attribute__((progmem))'
//-----------------------------------------------------

But I have followed the avr-libc example exactly.
So why is this error thrown and whats the correct way to do this ?

Thank You.
-- 
Best Regards,

-- Royce Pereira