Add support for specifying compiler options for mpers builds

Add support for specifying compiler options for mpers builds

Because some architectures are very, very special.

* configure.ac (cc_flags_m32, cc_flags_mx32): New variables. AC_SUBST
them.
* m4/mpers.m4 (MPERS_CFLAGS): Use instead of CFLAG, pushdef as
$cc_flags_$1.
Use mpers_name instead of CFLAG in AC_CACHE_CHECK messages.
Pass MPERS_CFLAGS as the second argument to mpers_test.sh
* mpers.sh: Add CC_ARCH_FLAGS as the second argument (PARSER_FILE
is moved to the third one). Do not expect leading dash in ARCH_FLAG
anymore.
* mpers_test.sh (mpers_cc_flags): New variable, initialise to the second
command line argument.
Pass $mpers_name without leading dash to mpers.sh.
Pass $mpers_cc_flags as the second argument to mpers.sh ($sample is
the third argument now).
* Makefile.am (mpers-m%.stamp:): Pass $(mpers_CC_FLAGS) as the second
argument to mpers.sh ($$f is now the third argument).
($(mpers_m32_targets)): Define target variable mpers_CC_FLAGS with the
value of @cc_flags_m32@
($(mpers_mx32_targets)): Define target variable mpers_CC_FLAGS with the
value of @cc_flags_mx32@
* tests/Makefile.am (MERS_CC_FLAGS): New variable.
* bootstrap: Append @cc_flags_$1@ to MPERS_CC_FLAGS. Append
$(MPERS_CC_FLAGS) to ARCH_MFLAGS.