rewrite+improve asm parsing

- We now let the parser call the firm backend for constraint checking:
   - Error messages are displayed in parsing phase already and not delayed
     for ast2firm
   - We don't need to unconditionally set address_taken on all asm
   	 arguments
- Note: this also "fixes" testsuite/x86code/asm_test13.c. This is due to less
  unnecessary address taken being used, it does NOT fix the missing
  must-be-same handling in libfirm.
implement support for namend assembler operands
improve target triplet parsing with missing manufacturer

sparc-elf is accepted now.
update libfirm revision
asm without arguments is interpreted differently
fix named asm arguments
ast: Restore the regular pattern to print asm statements.
preprocessor: Define _POSIX_C_SOURCE to access asctime_r().

This supersedes _POSIX_SOURCE.
Add optimization of occult constants

Placed after deconv, because it could be done inside deconv as well,
if we would use Seltenreich's version.
move call semantic checks into an own function

This also slightly changes the reported position for call errors to the
point of the opening brace.
rename lengthof() to ARRAY_SIZE()

this is to be consistent with libFirm code
change -mXXX flag handling

we now collect the flags upfront and pass them to the firm backend after
all other options. This ensures that we now the correct firm backend and
can translate an option like "-mfpmath=sse" into "-bia32-fpmath=sse".
support typegeneric builtin, add __sync_val_compare_and_swap
fix invalid clobber error
preprocessor: Avoid unnecessary deep recursion when checking for line splicing.

This caused a way too large number of put_back()s and overflowed the input buffer.
disabled reassociation phases