build failure, geo/qlandkarte

This broke on my last i386 bulk:

FAILED: src/CMakeFiles/qlandkartegt.dir/CMap3D.cpp.o
/usr/obj/ports/qlandkartegt-1.8.1/bin/c++ -DDB_VERSION=9 -DENABLE_TRANSLATION -DGPX_EXTENSIONS -DHAS_DBUS -DHAS_DMTX -DHAS_EXIF -DHAS_GPSD -DQT_CORE_LIB -DQT_GUI_LIB -DQT_NO_DEBUG -DVER_MAJOR=1 -DVER_MINOR=8 -DVER_STEP=1 -D_TTY_POSIX_ -Isrc -I/usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/src -I. -I/usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/include -I/usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/3rdparty/QZip -I/usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/3rdparty/QTextHtmlExporter -I/usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/3rdparty/QDeviceWatcher -I/usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/3rdparty/getopt -I/usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/3rdparty/qtsoap -I/usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/3rdparty/SerialPort/qextserialport -I/usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/3rdparty/SerialPort -I/usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/3rdparty/tzone/include -isystem /usr/local/include/X11/qt4 -isystem /usr/local/include/X11/qt4/QtGui -isystem /usr/local/include/X11/qt4/QtCore -I/usr/X11R6/include -I/usr/local/include -I/usr/local/include/X11/qt4/QtXml -I/usr/local/include/X11/qt4/QtSql -I/usr/local/include/X11/qt4/QtOpenGL -I/usr/local/include/X11/qt4/QtNetwork -I/usr/local/include/X11/qt4/QtDBus -I/usr/local/include/X11/qt4/QtWebKit -I/usr/local/include/X11/qt4/QtScript -I/usr/local/include/libexif -O2 -pipe -DGDALWARP=\"/usr/local/bin/gdalwarp\" -DGDALTRANSLATE=\"/usr/local/bin/gdal_translate\" -DGDALADDO=\"/usr/local/bin/gdaladdo\" -DGPSBABEL=\"/usr/local/bin/gpsbabel\" -DMAP2JNX=\"map2jnx\" -DNDEBUG -Wall -MD -MT src/CMakeFiles/qlandkartegt.dir/CMap3D.cpp.o -MF src/CMakeFiles/qlandkartegt.dir/CMap3D.cpp.o.d -o src/CMakeFiles/qlandkartegt.dir/CMap3D.cpp.o -c /usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/src/CMap3D.cpp
/usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/src/CMap3D.cpp: In member function 'void CMap3D::drawElevation(QPainter&)':
/usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/src/CMap3D.cpp:1348: error: 'isinf' was not declared in this scope
/usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/src/CMap3D.cpp: In member function 'void CMap3D::adjustElevationToMap()':
/usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/src/CMap3D.cpp:1982: error: 'isinf' was not declared in this scope
/usr/obj/ports/qlandkartegt-1.8.1/qlandkartegt-1.8.1/src/CMap3D.cpp:1992: error: 'isnan' was not declared in this scope
ninja: build stopped: subcommand failed.

Dep changes since the last build (which was successful):

-cmake-3.7.2p0
-gdal-2.2.0
+cmake-3.7.2p2
+gdal-2.2.1

Full log attached.