previous redeclaration of int sprintf under Mingw64

[robe]

Can't compile trunk under Mingw64

make[1]: Entering directory `/projects/gdal/branches/2.1/gdal/port'
/bin/sh /projects/gdal/branches/2.1/gdal/libtool --mode=compile --tag=CXX x86_64-w64-mingw32-g++ -I/projects/gdal/branches/2.1/gdal/port -I/projects/gdal/branches/2.1/gdal/gcore  -I/projects/gdal/branches/2.1/gdal/alg  -I/projects/gdal/bran -I../frmt
libtool: compile:  x86_64-w64-mingw32-g++ -I/projects/gdal/branches/2.1/gdal/port -I/projects/gdal/branches/2.1/gdal/gcore -I/projects/gdal/branches/2.1/gdal/alg -I/projects/gdal/branches/2.1/gdal/ogr -I/projects/gdal/branches/2.1/gdal/ogr/ogrsf_frmt
In file included from cpl_port.h:128:0,
                 from cpl_conv.h:35,
                 from cpl_conv.cpp:43:
c:/ming64gcc48/mingw64/x86_64-w64-mingw32/include/stdio.h:307:5: error: previous declaration of 'int sprintf(char*, const char*, ...)' with 'C++' linkage
 int sprintf (char *__stream, const char *__format, ...)
     ^
In file included from cpl_conv.h:35:0,
                 from cpl_conv.cpp:43:
cpl_port.h:828:85: error: conflicts with new declaration with 'C' linkage
     #define CPL_WARN_DEPRECATED(x)                       __attribute__ ((deprecated))
                                                                                     ^
cpl_port.h:847:74: note: in expansion of macro 'CPL_WARN_DEPRECATED'
 int sprintf(char *str, const char* fmt, ...) CPL_PRINT_FUNC_FORMAT(2, 3) CPL_WARN_DEPRECATED("Use snprintf() or CPLsnprintf() instead");
                                                                          ^
../GDALmake.opt:661: recipe for target `cpl_conv.lo' failed
make[1]: *** [cpl_conv.lo] Error 1
make[1]: Leaving directory `/projects/gdal/branches/2.1/gdal/port'
GNUmakefile:71: recipe for target `port-target' failed
make: *** [port-target] Error 2
make: *** No rule to make target `check'.  Stop.

I was able to about a month ago. I'll double-check 2.0 to see if have same issue

[Even Rouault]

trunk r33609 "Fix build with x86_64-w64-mingw32 4.8 (#6390)"