[lmi] Native compiler much faster [Was: Compiling takes longer with gcc-4.9.2]

[Greg Chicares]

On 2015-12-22 00:28, Greg Chicares wrote:
> My local tree contains makefile changes to use MinGW-w64 gcc-4.9.2,
> with '-std=c++11', some new warning flags, and various other
> adjustments.
[...]
> The bottom line:
>   3:19 = 199s gcc-3.4.5, std=gnu++98
>   7:32 = 452s gcc-4.9.2, std=c++03
>   9:18 = 558s gcc-4.9.2, std=c++11

    5:05 = 305s gcc-4.9.1, std=c++11, native toolchain
    ^^^^
Same ("old") machine, c++11, MinGW-w64 gcc-4.9.1 *native*:

/lmi/src/lmi[0]$rm -rf /lmi/src/build/lmi/CYGWIN_NT-5.1/gcc/ship
/lmi/src/lmi[0]$time make --jobs=12 install check_physical_closure >../log 2>&1
make --jobs=12 install check_physical_closure > ../log 2>&1
16.37s user 27.14s system 14% cpu 5:04.95 total

I can probably tune it better, but already we can conclude that
the cygwin-cross-compiler overhead was the worst problem.