-Wextra is only understood by GCC 3.4.6 or later.

-Wextra is only understood by GCC 3.4.6 or later.
It is a more descriptive synonym for -W.

Use -W instead which is understood by all common versions of GCC
(i.e. GCC 2.95 supports it, which is the oldest GCC version we have to support)

Additionally, conditionalise our -Werror usage on whether we're building for
BeOS/Haiku. On these platforms, the standard library headers result in warnings.
GCC 2 is quite happy to build this code on other platforms, so shouldn't be
the trigger for dropping -Werror (even if BeOS is the only target where GCC2 is
likely to be used).

svn path=/trunk/libsvgtiny/; revision=9670