+ ELF linker back-ends for ARM and MIPS.

ARM status: roughly corresponds to i386 one, passes the test suite. Handles libraries, can link static libc code including basic PIC and TLS IE/LE stuff. Completely misses Thumb support. Also does not handle ABI-specific stuff, for this reason internally linked .so cannot be used for linking executables with ld. Little-endian only. Tested only on "versatilepb" QEMU virtual machine.

MIPS status: can link the compiler and at least some dynamic executables including fpmake. Some PIC support is present but almost untested. Specific header flags and sections are also not handled yet. Written to handle both endian, but tested for big-endian only ("malta" QEMU VM), including cross-linking from x86_64.


git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@23376 3ad0048d-3df7-0310-abae-a5850022a9f2