Fix for __STRICT_ANSI__ being undefined

Leading to compile errors:

    [ 52%] Building CXX object libs/ptc/src/CMakeFiles/ptc.dir/tpsa.cpp.obj
    In file included from C:/msys64/ucrt64/include/c++/14.2.0/bits/requires_hosted.h:31,
                     from C:/msys64/ucrt64/include/c++/14.2.0/iostream:38,
                     from C:\Users\Thomas\dev\hit\cpymad\src\MAD-X\libs\ptc\src\tpsa.cpp:15:
    C:/msys64/ucrt64/include/c++/14.2.0/x86_64-w64-mingw32/bits/c++config.h:667:2: warning: #warning "__STRICT_ANSI__ seems to have been undefined; this is not supported" [-Wcpp]
      667 | #warning "__STRICT_ANSI__ seems to have been undefined; this is not supported"
          |  ^~~~~~~
    In file included from C:\Users\Thomas\dev\hit\cpymad\src\MAD-X\libs\ptc\src\tpsa.h:100,
                     from C:\Users\Thomas\dev\hit\cpymad\src\MAD-X\libs\ptc\src\tpsa.cpp:22:
    C:/msys64/ucrt64/include/c++/14.2.0/limits:2100:30: error: exponent has no digits
     2100 |         return __extension__ 0x1.0p-16382Q;
          |                              ^~~~~~
    C:/msys64/ucrt64/include/c++/14.2.0/limits:2100:37: error: invalid suffix "Q" on integer constant
     2100 |         return __extension__ 0x1.0p-16382Q;
          |                                     ^~~~~~
    C:/msys64/ucrt64/include/c++/14.2.0/limits:2114:30: error: exponent has no digits
     2114 |         return __extension__ 0x1.ffffffffffffffffffffffffffffp+16383Q;
          |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    C:/msys64/ucrt64/include/c++/14.2.0/limits:2114:64: error: invalid suffix "Q" on integer constant
     2114 |         return __extension__ 0x1.ffffffffffffffffffffffffffffp+16383Q;
          |                                                                ^~~~~~
    C:/msys64/ucrt64/include/c++/14.2.0/limits:2183:30: error: exponent has no digits
     2183 |         return __extension__ 0x1.0p-16494Q;
          |                              ^~~~~~
    C:/msys64/ucrt64/include/c++/14.2.0/limits:2183:37: error: invalid suffix "Q" on integer constant
     2183 |         return __extension__ 0x1.0p-16494Q;
          |                                     ^~~~~~

.github/build/windows/madx.sh

@@ -24,6 +24,7 @@ if [[ ! -f CMakeCache.txt ]]; then
         -DMADX_STATIC=ON \
         -DCMAKE_INSTALL_PREFIX=../dist \
         -DCMAKE_BUILD_TYPE=Release \
+        -DCMAKE_CXX_STANDARD=11 \
         -DMADX_INSTALL_DOC=OFF \
         -DMADX_ONLINE=OFF \
         -DMADX_FORCE_32=OFF \