MinGW-W64 compile error

Hi, I'm trying to build the client library of PostgreSql 9.3.x using
this version of MinGW's gcc:

gcc.exe (i686-posix-dwarf-rev0, Built by MinGW-W64 project) 5.2.0

I did a ./configure --without-zlib

then make (mingw32-make.exe), and got this:

$ /e/MinGW/mingw32/bin/mingw32-make.exe
E:/MinGW/mingw32/bin/mingw32-make -C src all
mingw32-make[1]: Entering directory 'E:/postgresql-9.3.10/src'
E:/MinGW/mingw32/bin/mingw32-make -C common all
mingw32-make[2]: Entering directory 'E:/postgresql-9.3.10/src/common'
E:/MinGW/mingw32/bin/mingw32-make -C ../backend submake-errcodes
mingw32-make[3]: Entering directory 'E:/postgresql-9.3.10/src/backend'
mingw32-make[3]: Nothing to be done for 'submake-errcodes'.
mingw32-make[3]: Leaving directory 'E:/postgresql-9.3.10/src/backend'
g++  -DFRONTEND -I../../src/include -I./src/include/port/win32
-DEXEC_BACKEND  "-I../../src/include/port/win32" -DBUILDING_DLL  -c -o
relpath.o relpath.c
relpath.c: In function 'int forkname_chars(const char*, ForkNumber*)':
relpath.c:55:15: error: invalid conversion from 'int' to 'ForkNumber'
[-fpermissive]
   for (forkNum = 1; forkNum <= MAX_FORKNUM; forkNum++)
                ^
relpath.c:55:51: error: no 'operator++(int)' declared for postfix '++'
[-fpermissive]
   for (forkNum = 1; forkNum <= MAX_FORKNUM; forkNum++)
                                                    ^
<builtin>: recipe for target 'relpath.o' failed
mingw32-make[2]: *** [relpath.o] Error 1
mingw32-make[2]: Leaving directory 'E:/postgresql-9.3.10/src/common'
makefile:34: recipe for target 'all-common-recurse' failed
mingw32-make[1]: *** [all-common-recurse] Error 2
mingw32-make[1]: Leaving directory 'E:/postgresql-9.3.10/src'
GNUmakefile:11: recipe for target 'all-src-recurse' failed
mingw32-make: *** [all-src-recurse] Error 2

Does anyone know how can I get rid of this error?.

Regards,

--
Leonardo M. Ramé
http://leonardorame.blogspot.com