converters/wkhtmltopdf: future-proof compiler version check
During an exp-run for llvm 14 (see bug 261742), it turned out that
converters/wkhtmltopdf fails to build with clang 14:
c++ -Wl,-rpath=/usr/local/lib/gcc8 -Wl,-O1 -pthread -shared -Wl,-soname,libwkhtmltox.so.0 -o libwkhtmltox.so.0.12.6 loadsettings.o logging.o multipageloader.o tempfile.o converter.o websettings.o reflect.o utilities.o pdfsettings.o pdfconverter.o outline.o tocstylesheet.o imagesettings.o imageconverter.o pdf_c_bindings.o image_c_bindings.o moc_multipageloader_p.o moc_converter_p.o moc_pdfconverter_p.o moc_imageconverter_p.o moc_pdf_c_bindings_p.o moc_image_c_bindings_p.o moc_converter.o moc_multipageloader.o moc_utilities.o moc_pdfconverter.o moc_imageconverter.o qrc_wkhtmltopdf.o -L/usr/local/lib -L/wrkdirs/usr/ports/converters/wkhtmltopdf/work/wkhtmltopdf-0.12.6/build/qt/lib -L/wrkdirs/usr/ports/converters/wkhtmltopdf/work/wkhtmltopdf-0.12.6/build/qt/plugins/codecs -lqcncodecs -L/wrkdirs/usr/ports/converters/wkhtmltopdf/work/wkhtmltopdf-0.12.6/build/qt/lib -L/usr/local/lib -lqjpcodecs -lqkrcodecs -lqtwcodecs -lQtWebKit -lQtSvg -lQtXmlPatterns -lQtGui -ljpeg -lpng -lXrender -lfontconfig -lfreetype -lXext -lX11 -lQtNetwork -lssl -lcrypto -lQtCore -lz -lm
ld: error: unable to find library -lQtWebKit
c++: error: linker command failed with exit code 1 (use -v to see invocation)
gmake[2]: *** [Makefile:164: ../../bin/libwkhtmltox.so.0.12.6] Error 1
Ultimately this is caused by incorrect compiler version detection in
wkhtmltopdf's configure script. Something similar was fixed for clang 12
in ports commit 1049d80399ac327964eca41e4188f988430c5f7c, and later for
clang 13 in ports commit ad5fedf36832fd7e2447d8c4cb6b54128a2fcb20.
To fix this, future-proof the compiler version check, at least until it
goes higher than 99.x.
PR: 262814
Approved by: pi (maintainer)
MFH: 2022Q1