Versions compatibility questions

Versions compatibility questions

[Philippe Gamba - Sun Microsystems]

Hello,

Using gcc on Solaris (2.5.1, 2.6 or 2.8), I would like to understand 2
differences between the 2 versions of gcc I work with :
"oldest"   one       : 2.7.2.1
"newest" one    : egcs-2.91.66


       If I link with 2.7.2.1, the binary generated has very few symbols
in dynsym (dynamic symbol table). That provoques run-time linker to fail

       because of 'unresolved symbol'error.

       If I link with egcs-2.91.66, the binary generated has a complete
dynsym. The run-time linker succeeds. But I cannot compile with my
       usual options that are : $ /usr/gnu/bin/gcc -c  -MDupdate
SunOS5.6_DBG.OBJ/.md <file>.c
       $ gcc: unrecognized option `-MDupdate'
       This option is correct with 2.7.2.1

- why 2.7.2.1 does not generate a full dynsym ?
- why egcs-2.91.66 does not understand -MDupdate ?
and more over what is the best solution to have both working ?

Thanks a lot for any explanation,

Philippe