cygport compile command fails

[Tatsuro MATSUOKA]

> ----- Original Message -----
> 
> Tatsuro MATSUOKA writes:
> >> > In file included from /usr/src/qt5-base-5.9.4-2.src/qt5-base-5.9.4-2.x86_64/src/qtbase-opensource-src-5.9.4/src/corelib/tools/qbytearray.cpp:42:
> >> > /usr/src/qt5-base-5.9.4-2.src/qt5-base-5.9.4-2.x86_64/src/qtbase-opensource-src-5.9.4/src/corelib/tools/qbytearraymatcher.h: In static member function ‘static QStaticByteArrayMatcherBase::Skiptable QStaticByteArrayMatcherBase::generate(const char*, uint)’:
> >> > /usr/src/qt5-base-5.9.4-2.src/qt5-base-5.9.4-2.x86_64/src/qtbase-opensource-src-5.9.4/src/corelib/tools/qbytearraymatcher.h:103:38: error: ‘numeric_limits’ is not a member of ‘std’
> >> >    103 |         const auto uchar_max = (std::numeric_limits<uchar>::max)();
> >> >        |                                      ^~~~~~~~~~~~~~
> >> > /usr/src/qt5-base-5.9.4-2.src/qt5-base-5.9.4-2.x86_64/src/qtbase-opensource-src-5.9.4/src/corelib/tools/qbytearraymatcher.h:103:58: error: expected primary-expression before ‘>’ token
> >> >    103 |         const auto uchar_max = (std::numeric_limits<uchar>::max)();
> >> >        |                                                          ^
> >> > /usr/src/qt5-base-5.9.4-2.src/qt5-base-5.9.4-2.x86_64/src/qtbase-opensource-src-5.9.4/src/corelib/tools/qbytearraymatcher.h:103:61: error: ‘::max’ has not been declared; did you mean ‘std::max’?
> >> >    103 |         const auto uchar_max = (std::numeric_limits<uchar>::max)();
> >> >        |                                                             ^~~
> >> >        |                                                             std::max
> 
> The default C++ standard targeted by gcc-11 is gnu++17.
> 
> Given how old Qt5 is and that the upstream packages were compiled w/
> gcc-7 mostly, I'd guess you should either add -std=gnu++11 or
> -std=gnu++14 to the CXXFLAGS.
> 
> 
> Regards,
> Achim.

Dear Achim

Downgrading gcc-11 from gcc-10, the above error disappeared.
I met another errors. But those are not related to g++.

I will tell cygwin-ML by another thread.

Tatsuro