The Makefile generation of Qwt6s designer plugin goes a bit awry and produces this (r:/build/kdesupport/qwt6-20110806/work/mingw4-RelWithDebInfo-6.0.1/designer/Makefile.Release): [...] @echo rcc ..\..\qwt-6.0.1\designer\qwt_designer_plugin.qrc && .\bin\rcc.exe -name qwt_designer_plugin ..\..\qwt-6.0.1\designer\qwt_designer_plugin.qrc -o resources\qrc_qwt_designer_plugin.cpp [...] .\bin\rcc.exe is of course not a valid path in that folder, so the build fails: http://paste.kde.org/617972/ Reproducible: Always Steps to Reproduce: 1. emerge qwt6
This is a bug in Qt and apparently fixed in 4.8.4: https://bugreports.qt-project.org/browse/QTBUG-27237?focusedCommentId=184187&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-184187 The workaround proposed by Daniel Frömmel in the comments worked fine for me.