This backports a patch from Qt 5.6 that fixed a SIGFPE when using Xvfb. I've tested this with an updated ruby-capybara-webkit running using Xvfb and confirmed that it fixes the issue.
OK? Thanks, Jeremy Index: Makefile =================================================================== RCS file: /cvs/ports/x11/qt5/Makefile,v retrieving revision 1.52 diff -u -p -r1.52 Makefile --- Makefile 6 Sep 2016 09:00:19 -0000 1.52 +++ Makefile 20 Sep 2016 22:40:04 -0000 @@ -19,7 +19,7 @@ COMMENT-sqlite2 = SQLite 2.x plugin for COMMENT-tds = TDS plugin for Qt5 PKGNAME-main = qt5-${VERSION} -REVISION-main = 1 +REVISION-main = 2 PKGNAME-examples = qt5-examples-${VERSION} REVISION-examples = 0 PKGNAME-html = qt5-html-${VERSION} Index: patches/patch-qtbase_src_plugins_platforms_xcb_qxcbscreen_cpp =================================================================== RCS file: patches/patch-qtbase_src_plugins_platforms_xcb_qxcbscreen_cpp diff -N patches/patch-qtbase_src_plugins_platforms_xcb_qxcbscreen_cpp --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ patches/patch-qtbase_src_plugins_platforms_xcb_qxcbscreen_cpp 20 Sep 2016 22:51:57 -0000 @@ -0,0 +1,17 @@ +$OpenBSD$ + +Fix SIGFPE when using Xvfb, backported from Qt 5.6 +(https://codereview.qt-project.org/#/c/140411/). + +--- qtbase/src/plugins/platforms/xcb/qxcbscreen.cpp.ports.orig Tue Sep 20 15:49:42 2016 ++++ qtbase/src/plugins/platforms/xcb/qxcbscreen.cpp Tue Sep 20 15:50:09 2016 +@@ -544,7 +544,8 @@ void QXcbScreen::updateRefreshRate(xcb_randr_mode_t mo + for (; modesIter.rem; xcb_randr_mode_info_next(&modesIter)) { + xcb_randr_mode_info_t *modeInfo = modesIter.data; + if (modeInfo->id == mode) { +- m_refreshRate = modeInfo->dot_clock / (modeInfo->htotal * modeInfo->vtotal); ++ const uint32_t dotCount = modeInfo->htotal * modeInfo->vtotal; ++ m_refreshRate = (dotCount != 0) ? modeInfo->dot_clock / dotCount : 0; + m_mode = mode; + break; + }