Make parse_btype only accept one basic type

This makes int char c; and struct {} int c; generate an error. Thanks
Mobi Phil for reporting.

Conflicts:

	tccgen.c
Deprecate FPA and OABI support for ARM

Conflicts:

	arm-gen.c
Warn about soft float ABI not being supported

For ARM target, tcc uses the soft float ABI when not asked to use hard
float ABI. This means machine without a VFP co-processor generate code
that they cannot run. This commit add a warning for such cases.

Conflicts:

	arm-gen.c
Add test for previous commit

* Adapt tests2 Makefile to support testing tcc error reporting
* Add test for previous commit
Always link libtcc1.a in (useful for va_* on x86)

On x86 tcc call to function in libtcc1.a to implement va_* functions.

Conflicts:

	tccelf.c
A possible fix for the memory leak reported by valgrind when running tcctest.c with tcc.

Conflicts:

	libtcc.c
	tccelf.c
Simplify and fix GOT32 + PLT32 reloc commit

Introduce a new attribute to check the existence of a PLT entry for a
given symbol has the presence of an entry for that symbol in the dynsym
section is not proof that a PLT entry exists.

This fixes commit dc8ea93b13faefb565fb937f8b8c08c40c063549.

Conflicts:

	tccelf.c
Fix for the crash on linux 64 bits, the problem was garbage on stack variables that are unions taht write to one small type and read from a bigger type.