Mingw32 build failed

[saitej09]

I am trying to compile using mingw32 (msys) with the following compiler:
COLLECT_GCC=C:\MinGW\bin\g++.exe
COLLECT_LTO_WRAPPER=c:/mingw/bin/../libexec/gcc/mingw32/4.9.3/lto-wrapper.exe
Target: mingw32
Configured with: ../src/gcc-4.9.3/configure --build=x86_64-pc-linux-gnu --host=mingw32 --prefix=/mingw --disable-win32-registry --target=mingw32 --with-arch=i586 --enable-languages=c,c++,objc,obj-c++,fortran,ada --enable-static --enable-shared --enable-threads --with-dwarf2 --disable-sjlj-exceptions --enable-version-specific-runtime-libs --enable-libstdcxx-debug --with-tune=generic --enable-nls
Thread model: win32
gcc version 4.9.3 (GCC)

I get this error during make:
time_util.cc:43:35: error: use of C++11 long long integer constant [-Werror=long-long]
#define DELTA_EPOCH_IN_MICROSECS 11644473600000000ULL
^
time_util.cc:58:18: note: in expansion of macro 'DELTA_EPOCH_IN_MICROSECS'
file_time64 -= DELTA_EPOCH_IN_MICROSECS;
^
cc1plus.exe: all warnings being treated as errors

I tried adding c++11 flags to make file:
CXXFLAGS = -g -O2 -std=c++11 but it gives the same error.