Shame on me!
I have to post a new patch because an AMD Bulldozer identification pattern was wrong.

(file #31917)

I posted an article (memo) containing detailed data and script used to rewrite this macro at <http://a4lg.com/memo/2014-08-16/ax_gcc_archflag-x86-rewrite-details.html>.

`case' patterns and CPUID identification patterns on AX_GCC_ARCHFLAG are quite old and not robust enough to support future processors.
I decided to rewrite x86 support to make them robust. I used a Python script to generate robust patterns and verified all processor identification patterns are "genuine".

Originally, I planned to submit this patch by multiple patches (to do the separate "change" one by one) but I found several fixes have cross dependencies and "intermediate" versions of macro were nearly unusable (partially because of "incomplete" fixes and partially because of known issue on Clang). If this is inappropriate, please comment that.

Anyway, this patch includes several kinds of fixes and additions.
There are following changes.

[CPUID ROBUSTNESS]

• Rewritten CPUID identification (constructed by a script).
• Check EDX/ECX (not only EBX) on vendor identification.

[SIMPLIFICATION]

• Simplify some Intel/AMD processor support (because most compilers merge support for same/similar microarchitecture, even if they have different brand names).

[BUG FIXES (except possible issues fixed in CPUID ROBUSTNESS section)]

• Fix 64-bit FreeBSD support.
• Fix support for AMD K6-2+/K6-III+ (because they are K6-3 based, not K6-2 based)
• Fix support for AMD family 11h (some mobile processors based on K8 but misunderstood as amdfam10)

[PROCESSOR SUPPORT]

• Make all CPUID patterns "evidence-based" (to never mix fallbacks and actual processors)
• Remove all CPU support which existence of processor could not be confirmed by official documents.
• Add AMD Piledriver/Steamroller/Jaguar support
• Add Intel Atom (Bonnell/Silvermont) support
• Add Intel Ivy Bridge/Haswell/Broadwell support
• Add support for some Centaur-based processors (some Cyrix III models, some WinChip models, some VIA C3 models, VIA C7 and later)

[COMPILER SUPPORT]

• Add further compiler support for GCC 4.9/LLVM Clang.

[KNOWN ISSUE]
Clang does not fail if -mtune=[UNKNOWN_PROCESSOR] and/or -mcpu=[UNKNOWN_PROCESSOR] are specified. We need to fix Clang support later (by change order of option checking).