GCC 15 Bids Farewell To Solaris 11.3 Support

With GCC 14 stable released and GCC 15 now in development on trunk, new feature code is landing for the GNU Compiler Collection. Among the early features is Microsoft contributing the "Windows on ARM64" target with aarch64-w64-mingw32. The start of the new cycle also brings code removal for features deprecated in prior cycles. Among the old code being cleared out in GCC 15 is saying goodbye to Oracle Solaris 11.3.

Solaris 11.3 support was already declared obsolete back in GCC 13 while now with GCC 15 it will no longer exist. This commit drops Solaris 11.3 support while making alterations around the existing Solaris 11.4 support.

GCC 15 is also expected to drop support for Intel Xeon Phi processors, remove the Intel Itanium IA64 targets after being unmaintained for years, and also drop the NIOS2 targets. As usual, GCC 15 will be out around this time next year.