shiboken2 receives SIGSEGV when trying to build the Falkon web browser from
source with Python plugins.

Steps to reproduce the bug (prerequisites: python3-pyside2-devel, clang-devel,
...):

$ git clone https://invent.kde.org/network/falkon.git
$ cd falkon
$ mkdir build && cd build
$ cmake -DCMAKE_INSTALL_PREFIX=/opt/falkon -DCMAKE_BUILD_TYPE=None ..
$ LC_ALL=C make

After that the error can be reproduced by 

$ cd src/plugins/PyFalkon

and executing /usr/bin/shiboken2 with a long list of arguments found with

$ grep shiboken2 CMakeFiles/PyFalkon_autogen.dir/build.make

Backtrace obtained with 'coredumpctl debug':

(gdb) bt
#0  llvm::StringMapEntryBase::getKeyLength (this=<optimized out>) at
../include/llvm/ADT/StringMapEntry.h:29
#1  llvm::StringMapEntry<llvm::ErrorOr<clang::FileEntryRef::MapValue> >::first
(this=<optimized out>) at ../include/llvm/ADT/StringMapEntry.h:85
#2  clang::FileEntryRef::getName (this=0x7f4f2f2b89b0) at
../tools/clang/include/clang/Basic/FileEntry.h:62
#3  clang::FileEntry::getName (this=0x7f4f2f2b8950) at
../tools/clang/include/clang/Basic/FileEntry.h:364
#4  clang_getFileName (SFile=0x7f4f2f2b8950) at
../tools/clang/tools/libclang/CIndex.cpp:4333
#5  0x000055d81c82703a in clang::operator<<(QDebug, clang::SourceLocation
const&) ()
#6  0x000055d81c8272fb in clang::operator<<(QDebug, clang::Diagnostic const&)
()
#7  0x000055d81c7b22b6 in
AbstractMetaBuilderPrivate::buildDom(QList<QByteArray>, LanguageLevel, unsigned
int) ()
#8  0x000055d81c7b9dd8 in AbstractMetaBuilder::build(QList<QByteArray> const&,
LanguageLevel, unsigned int) ()
#9  0x000055d81c79fe42 in ApiExtractor::run() ()
#10 0x000055d81c6ff570 in main ()