Can not compile qtopcua without .git directory

klaus@klaus-MS-7823:~/Downloads$ git clone https://code.qt.io/qt/qtopcua.git
Klone nach 'qtopcua' ...
remote: Counting objects: 8622, done.
remote: Compressing objects: 100% (4649/4649), done.
remote: Total 8622 (delta 5364), reused 6340 (delta 3892)
Empfange Objekte: 100% (8622/8622), 2.55 MiB | 5.18 MiB/s, Fertig.
Löse Unterschiede auf: 100% (5364/5364), Fertig.
klaus@klaus-MS-7823:~/Downloads$ cd qtopcua
klaus@klaus-MS-7823:~/Downloads/qtopcua$ git checkout 5.15
Branch '5.15' folgt nun Remote-Branch '5.15' von 'origin'.
Zu neuem Branch '5.15' gewechselt
klaus@klaus-MS-7823:~/Downloads/qtopcua$ PATH=$PATH:/home/klaus/Downloads/mxe/usr/bin
klaus@klaus-MS-7823:~/Downloads/qtopcua$ /home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/bin/qmake "CONFIG+=release"  "QMAKE_CXXFLAGS +=-fpermissive"
Info: creating stash file /home/klaus/Downloads/qtopcua/.qmake.stash
Info: creating cache file /home/klaus/Downloads/qtopcua/.qmake.cache

Running configuration tests...
Checking for mbedtls... no
Checking for Open62541... no
Checking for Unified Automation C++ SDK... no
Done running configuration tests.

Configure summary:

Qt Opcua:
  Open62541 .............................. yes
  Unified Automation C++ SDK ............. no
  Support for namespace 0 NodeId names ... yes
  Namespace 0 NodeIds generator .......... no
  mbedtls ................................ no
  Support for global discovery server .... yes

Qt is now configured for building. Just run 'make'.
Once everything is built, you must run 'make install'.
Qt will be installed into '/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5'.

Prior to reconfiguration, make sure you remove any leftovers from
the previous build.

klaus@klaus-MS-7823:~/Downloads/qtopcua$ make
cd src/ && ( test -e Makefile || /home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/bin/qmake -o Makefile /home/klaus/Downloads/qtopcua/src/src.pro CONFIG+=release 'QMAKE_CXXFLAGS +=-fpermissive' ) && make -f Makefile 
make[1]: Verzeichnis „/home/klaus/Downloads/qtopcua/src" wird betreten
cd opcua/ && ( test -e Makefile || /home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/bin/qmake -o Makefile /home/klaus/Downloads/qtopcua/src/opcua/opcua.pro CONFIG+=release 'QMAKE_CXXFLAGS +=-fpermissive' ) && make -f Makefile 
Project MESSAGE: perl -w /home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/bin/syncqt.pl -module QtOpcUa -version 5.15.1 -outdir /home/klaus/Downloads/qtopcua -builddir /home/klaus/Downloads/qtopcua /home/klaus/Downloads/qtopcua
<srcbase> = /home/klaus/Downloads/qtopcua 
<bldbase> = /home/klaus/Downloads/qtopcua 
<outbase> = /home/klaus/Downloads/qtopcua 
QtOpcUa: created fwd-include header(s) for <srcbase>/src/opcua/ { qopcuaglobal.h (1) }
QtOpcUa: created fwd-include header(s) for <srcbase>/src/opcua/client/ { qopcuaaddnodeitem.h (2), qopcuaaddreferenceitem.h (2), qopcuaapplicationdescription.h (2), qopcuaapplicationidentity.h (2), qopcuaapplicationrecorddatatype.h (2), qopcuaargument.h (2), qopcuaattributeoperand.h (2), qopcuaauthenticationinformation.h (2), qopcuaaxisinformation.h (2), qopcuabackend_p.h (1), qopcuabinarydataencoding.h (2), qopcuabrowsepathtarget.h (2), qopcuabrowserequest.h (2), qopcuaclient.h (2), qopcuaclient_p.h (1), qopcuaclientimpl_p.h (1), qopcuacomplexnumber.h (2), qopcuacontentfilterelement.h (2), qopcuacontentfilterelementresult.h (2), qopcuadeletereferenceitem.h (2), qopcuadoublecomplexnumber.h (2), qopcuaelementoperand.h (2), qopcuaendpointdescription.h (2), qopcuaerrorstate.h (2), qopcuaeuinformation.h (2), qopcuaeventfilterresult.h (2), qopcuaexpandednodeid.h (2), qopcuaextensionobject.h (2), qopcuagdsclient.h (2), qopcuagdsclient_p.h (1), qopcualiteraloperand.h (2), qopcualocalizedtext.h (2), qopcuamonitoringparameters.h (2), qopcuamonitoringparameters_p.h (1), qopcuamultidimensionalarray.h (2), qopcuanode.h (2), qopcuanode_p.h (1), qopcuanodecreationattributes.h (2), qopcuanodecreationattributes_p.h (1), qopcuanodeids.h (1), qopcuanodeimpl_p.h (1), qopcuapkiconfiguration.h (2), qopcuaqualifiedname.h (2), qopcuarange.h (2), qopcuareaditem.h (2), qopcuareadresult.h (2), qopcuareferencedescription.h (2), qopcuarelativepathelement.h (2), qopcuasimpleattributeoperand.h (2), qopcuatype.h (1), qopcuausertokenpolicy.h (2), qopcuawriteitem.h (2), qopcuawriteresult.h (2), qopcuaxvalue.h (2) }
QtOpcUa: created fwd-include header(s) for <srcbase>/src/opcua/core/ { qopcuaplugin.h (2), qopcuaprovider.h (2) }
QtOpcUa: created fwd-include header(s) for <srcbase>/src/opcua/x509/ { openssl_symbols_p.h (1), qopcuakeypair.h (2), qopcuakeypair_p.h (1), qopcuax509certificatesigningrequest.h (2), qopcuax509certificatesigningrequest_p.h (1), qopcuax509distinguishedname.h (2), qopcuax509extension.h (2), qopcuax509extension_p.h (1), qopcuax509extensionbasicconstraints.h (2), qopcuax509extensionextendedkeyusage.h (2), qopcuax509extensionkeyusage.h (2), qopcuax509extensionsubjectalternativename.h (2), qopcuax509utils_p.h (1), qsslsocket_openssl11_symbols_p.h (1), qsslsocket_opensslpre11_symbols_p.h (1) }
QtOpcUa: created version header
QtOpcUa: created master header
QtOpcUa: created headers.pri file
make[2]: Verzeichnis „/home/klaus/Downloads/qtopcua/src/opcua" wird betreten
make -f Makefile.Release
make[3]: Verzeichnis „/home/klaus/Downloads/qtopcua/src/opcua" wird betreten
i686-w64-mingw32.shared-g++ -c -pipe -fno-keep-inline-dllexport -fpermissive -msse2 -mstackrealign -mfpmath=sse -O2 -std=c++1y -fno-exceptions -Wall -Wextra -Wextra -Wvla -Wdate-time -DUNICODE -D_UNICODE -DWIN32 -DMINGW_HAS_SECURE_API=1 -DWINVER=0x0601 -D_WIN32_WINNT=0x0601 -DQT_NO_LINKED_LIST -DQT_NO_NARROWING_CONVERSIONS_IN_CONNECT -DQT_BUILD_OPCUA_LIB -DQT_BUILDING_QT -D_CRT_SECURE_NO_WARNINGS -D_USE_MATH_DEFINES -DQT_NO_CAST_TO_ASCII -DQT_ASCII_CAST_WARNINGS -DQT_MOC_COMPAT -DQT_USE_QSTRINGBUILDER -DQT_DEPRECATED_WARNINGS -DQT_DISABLE_DEPRECATED_BEFORE=0x040800 -DQT_DEPRECATED_WARNINGS_SINCE=0x060000 -DQT_NO_FOREACH -DQT_NO_EXCEPTIONS -DQT_NO_DEBUG -DQT_NETWORK_LIB -DQT_CORE_LIB -DQ_USE_SYBASE -I. -I../../include -I../../include/QtOpcUa -I../../include/QtOpcUa/5.15.1 -I../../include/QtOpcUa/5.15.1/QtOpcUa -Itmp -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtNetwork/5.15.0 -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtNetwork/5.15.0/QtNetwork -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtCore/5.15.0 -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtCore/5.15.0/QtCore -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtNetwork -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtCore -I.moc/release -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/mkspecs/win32-g++  -o .obj/release/qopcuaprovider.o core/qopcuaprovider.cpp
core/qopcuaprovider.cpp: In function 'QHash<QString, QJsonObject> loadPluginMetadata()':
core/qopcuaprovider.cpp:110:82: warning: 'QHash<K, V>::iterator QHash<K, V>::insertMulti(const Key&, const T&) [with Key = QString; T = QJsonObject]' is deprecated: Use QMultiHash for hashes storing multiple values with the same key. [-Wdeprecated-declarations]
     plugins.insertMulti(obj.value(QStringLiteral("Provider")).toString(), obj);
                                                                              ^
In file included from core/qopcuaprovider.h:42:0,
                 from core/qopcuaprovider.cpp:38:
/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtCore/qhash.h:1225:55: note: declared here
 Q_OUTOFLINE_TEMPLATE typename QHash<Key, T>::iterator QHash<Key, T>::insertMult
                                                       ^
i686-w64-mingw32.shared-g++ -c -pipe -fno-keep-inline-dllexport -fpermissive -msse2 -mstackrealign -mfpmath=sse -O2 -std=c++1y -fno-exceptions -Wall -Wextra -Wextra -Wvla -Wdate-time -DUNICODE -D_UNICODE -DWIN32 -DMINGW_HAS_SECURE_API=1 -DWINVER=0x0601 -D_WIN32_WINNT=0x0601 -DQT_NO_LINKED_LIST -DQT_NO_NARROWING_CONVERSIONS_IN_CONNECT -DQT_BUILD_OPCUA_LIB -DQT_BUILDING_QT -D_CRT_SECURE_NO_WARNINGS -D_USE_MATH_DEFINES -DQT_NO_CAST_TO_ASCII -DQT_ASCII_CAST_WARNINGS -DQT_MOC_COMPAT -DQT_USE_QSTRINGBUILDER -DQT_DEPRECATED_WARNINGS -DQT_DISABLE_DEPRECATED_BEFORE=0x040800 -DQT_DEPRECATED_WARNINGS_SINCE=0x060000 -DQT_NO_FOREACH -DQT_NO_EXCEPTIONS -DQT_NO_DEBUG -DQT_NETWORK_LIB -DQT_CORE_LIB -DQ_USE_SYBASE -I. -I../../include -I../../include/QtOpcUa -I../../include/QtOpcUa/5.15.1 -I../../include/QtOpcUa/5.15.1/QtOpcUa -Itmp -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtNetwork/5.15.0 -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtNetwork/5.15.0/QtNetwork -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtCore/5.15.0 -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtCore/5.15.0/QtCore -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtNetwork -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtCore -I.moc/release -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/mkspecs/win32-g++  -o .obj/release/qopcuaplugin.o core/qopcuaplugin.cpp
.......

klaus@klaus-MS-7823:~/Downloads/qtopcua-5.15$ PATH=$PATH:/home/klaus/Downloads/mxe/usr/bin
klaus@klaus-MS-7823:~/Downloads/qtopcua-5.15$ /home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/bin/qmake "CONFIG+=release"  "QMAKE_CXXFLAGS +=-fpermissive"
Info: creating stash file /home/klaus/Downloads/qtopcua-5.15/.qmake.stash
Info: creating cache file /home/klaus/Downloads/qtopcua-5.15/.qmake.cache

Running configuration tests...
Checking for mbedtls... no
Checking for Open62541... no
Checking for Unified Automation C++ SDK... no
Done running configuration tests.

Configure summary:

Qt Opcua:
  Open62541 .............................. yes
  Unified Automation C++ SDK ............. no
  Support for namespace 0 NodeId names ... yes
  Namespace 0 NodeIds generator .......... no
  mbedtls ................................ no
  Support for global discovery server .... yes

Qt is now configured for building. Just run 'make'.
Once everything is built, you must run 'make install'.
Qt will be installed into '/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5'.

Prior to reconfiguration, make sure you remove any leftovers from
the previous build.

klaus@klaus-MS-7823:~/Downloads/qtopcua-5.15$ make
cd src/ && ( test -e Makefile || /home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/bin/qmake -o Makefile /home/klaus/Downloads/qtopcua-5.15/src/src.pro CONFIG+=release 'QMAKE_CXXFLAGS +=-fpermissive' ) && make -f Makefile 
make[1]: Verzeichnis „/home/klaus/Downloads/qtopcua-5.15/src" wird betreten
cd opcua/ && ( test -e Makefile || /home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/bin/qmake -o Makefile /home/klaus/Downloads/qtopcua-5.15/src/opcua/opcua.pro CONFIG+=release 'QMAKE_CXXFLAGS +=-fpermissive' ) && make -f Makefile 
make[2]: Verzeichnis „/home/klaus/Downloads/qtopcua-5.15/src/opcua" wird betreten
make -f Makefile.Release
make[3]: Verzeichnis „/home/klaus/Downloads/qtopcua-5.15/src/opcua" wird betreten
i686-w64-mingw32.shared-g++ -c -pipe -fno-keep-inline-dllexport -fpermissive -msse2 -mstackrealign -mfpmath=sse -O2 -std=c++1y -fno-exceptions -Wall -Wextra -Wextra -Wvla -Wdate-time -DUNICODE -D_UNICODE -DWIN32 -DMINGW_HAS_SECURE_API=1 -DWINVER=0x0601 -D_WIN32_WINNT=0x0601 -DQT_NO_LINKED_LIST -DQT_NO_NARROWING_CONVERSIONS_IN_CONNECT -DQT_BUILD_OPCUA_LIB -DQT_BUILDING_QT -D_CRT_SECURE_NO_WARNINGS -D_USE_MATH_DEFINES -DQT_NO_CAST_TO_ASCII -DQT_ASCII_CAST_WARNINGS -DQT_MOC_COMPAT -DQT_USE_QSTRINGBUILDER -DQT_DEPRECATED_WARNINGS -DQT_DISABLE_DEPRECATED_BEFORE=0x040800 -DQT_DEPRECATED_WARNINGS_SINCE=0x060000 -DQT_NO_FOREACH -DQT_NO_EXCEPTIONS -DQT_NO_DEBUG -DQT_NETWORK_LIB -DQT_CORE_LIB -DQ_USE_SYBASE -I. -I../../include -I../../include/QtOpcUa -I../../include/QtOpcUa/5.15.1 -I../../include/QtOpcUa/5.15.1/QtOpcUa -Itmp -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtNetwork/5.15.0 -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtNetwork/5.15.0/QtNetwork -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtCore/5.15.0 -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtCore/5.15.0/QtCore -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtNetwork -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/include/QtCore -I.moc/release -I/home/klaus/Downloads/mxe/usr/i686-w64-mingw32.shared/qt5/mkspecs/win32-g++  -o .obj/release/qopcuaprovider.o core/qopcuaprovider.cpp
In file included from core/qopcuaprovider.cpp:37:0:
core/qopcuaplugin.h:40:34: fatal error: QtOpcUa/qopcuaglobal.h: No such file or directory
compilation terminated.
make[3]: *** [Makefile.Release:1569: .obj/release/qopcuaprovider.o] Fehler 1
make[3]: Verzeichnis „/home/klaus/Downloads/qtopcua-5.15/src/opcua" wird verlassen
make[2]: *** [Makefile:45: release] Fehler 2
make[2]: Verzeichnis „/home/klaus/Downloads/qtopcua-5.15/src/opcua" wird verlassen
make[1]: *** [Makefile:52: sub-opcua-make_first] Fehler 2
make[1]: Verzeichnis „/home/klaus/Downloads/qtopcua-5.15/src" wird verlassen
make: *** [Makefile:53: sub-src-make_first] Fehler 2