Here's a test-case for you.  Save the attached source file as
/tmp/test.cpp and run the following g++ invocation:

g++ -c -g -O0 -fno-strict-aliasing -Wall -W -Wno-format-y2k \
  -Wpointer-arith -Wwrite-strings -o /tmp/test.o /tmp/test.cpp

When I run this command against the attached file I get:

/tmp/test.cpp: In function ¡Æint do_test()¡Ç:
/tmp/test.cpp:14: warning: deprecated conversion from string constant to ¡Æchar*¡Ç'

But if you look the argument IS a const, just through a typedef.
I'm using g++ 4.1.1-1 on FC5:

Using built-in specs.
Target: i386-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-libgcj-multifile --enable-languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk --disable-dssi --with-java-home=/usr/lib/jvm/java-1.4.2-gcj-1.4.2.0/jre --with-cpu=generic --host=i386-redhat-linux
Thread model: posix
gcc version 4.1.1 20060525 (Red Hat 4.1.1-1)

-derek