Request update of Target Platforms section

[Nathaniel Hayden]

According to the content itself ("As of 2011 ...") the section was last 
updated in 2011, and commit logs seem to confirm this.

I'm a developer in a bioinformatics group that uses the R statistical 
analysis language, also part of the GNU Project. I came across Gnulib 
while trying to port an important bioinformatics library (HTSlib) to 
Windows on the way to making it available in R. I've already had success 
with making the library work with mingw32. Thank you for your excellent 
work!

But the R language toolchain for Windows is based on MinGW-w64. 
Currently the Target Platforms section reads
    - mingw in 64-bit mode is not tested and low priority so far.

The logs contain many commits around MinGW-w64. Can you comment on 
support for MinGW-w64--and is it now considered a reasonable target, and 
hence the Target Platforms section can be updated? I would like to sell 
adoption of Gnulib to the maintainers of HTSlib, but the ultimate goal 
is to make it work with R's toolchain.

Thanks,
Nate Hayden

P.S In the hope that it's helpful, my imported modules are:
alloca arpa_inet fcntl fdatasync inttypes netdb recv send stat-size 
stddef stdint stdlib string sys_select sys_socket sys_stat sys_time unistd

With all dependencies included:
absolute-header alloca alloca-opt arpa_inet close dup2 errno extensions 
extern-inline fcntl fcntl-h fd-hook fdatasync fileblocks fsync 
getdtablesize gettimeofday include_next inttypes inttypes-incomplete 
msvc-inval msvc-nothrow multiarch netdb recv send signal-h 
snippet/_Noreturn snippet/arg-nonnull snippet/c++defs 
snippet/warn-on-use socketlib socklen ssize_t stat-size stdalign stddef 
stdint stdlib string sys_select sys_socket sys_stat sys_time sys_types 
sys_uio time unistd