Updates for improved reusability/clarity

[Martin Thuresson <martin at mtme dot org>]

I am interested in reusing parts of binutils/gas for a project I'm
working with. The project aims at doing analysis and optimizations at
the assembly level. While working I have noticed some possible changes
that I think are beneficial for the binutils community at large. Any
feedback on these suggested changes before I submit patches are
welcome.

1:
gas defines its own assert macro in as.h. Since assert is used in
standard libraries, both in C and C++, i propose to change the name
from assert to gas_assert.

2:
In bfd/elf-bfd.h, the union gotplt_unit is defined inside struct
elf_link_hash_entry, but is then used in other structs. This does not
compile with c++. I therefor suggest to move gotplt_unit.

3:
template is a keyword in C++. I suggest to change the name of the
template types in opcodes/i386-tbl.h and include/opcode/tic54x.h to
insn_template.

4:
Currently, i386_insn is defined in gas/config/tc-i386.c. I suggest to
move it to tc-i386.h to make it possible to reuse the data structure
in other files.

5:
Add the keyword explicit to the declaration of
dwarf2_loc_directive_seen and dwarf2_loc_mark_labels in
gas/dward2dbg.h. This makes it possible to use the header in C++
without getting multiple definitions errors. They are defined in
dwarf2dbg.c

Thanks,
Martin