gcc: promote PKGVERSION and BUGURL options to toolchain level

This patch promotes the PKGVERSION and BUGURL options to toolchain level so that
all toolchain components supporting them can benefit from them.

These options are passed to configure through --with-pkgversion and
--with-bugurl.

They are supported by binutils 2.18+, gcc 4.3+, eglibc 2.9+ and gdb 7.0+.

Signed-off-by: "Benoît THÉBAUDEAU" <benoit.thebaudeau@advansee.com>

 # m68k specific configuration file

 ## depends on EXPERIMENTAL

 ##

 ## select ARCH_SUPPORTS_32

 ## select ARCH_DEFAULT_32

 ## select ARCH_DEFAULT_BE

 ## select ARCH_SUPPORT_CPU

 ##

 ## help The m68k architecture