"Fancy" version statement (qmake part)

After some highly annoying and time consuming tinkering with quotes and
escaping, the embedding of versioning data seems to work as intended
now.

tools/linuxdeployqt/linuxdeployqt.pro

@@ -15,3 +15,19 @@ SOURCES += main.cpp \
 	shared.cpp
 
 DEFINES -= QT_USE_QSTRINGBUILDER #leads to compile errors if not disabled
+
+# versioning
+# don't break the quotes -- at the moment, the shell commands are injected into the Makefile to have them run on every
+# build and not during configure time
+
+DEFINES += LINUXDEPLOYQT_GIT_COMMIT="'\"$(shell git rev-parse --short HEAD)\"'"
+
+DEFINES += BUILD_DATE="'\"$(shell env LC_ALL=C date -u '+%Y-%m-%d %H:%M:%S %Z')\"'"
+
+equals($$(TRAVIS_BUILD_NUMBER), "") {
+    DEFINES += BUILD_NUMBER="'\"<local dev build>\"'"
+} else {
+    DEFINES += BUILD_NUMBER="'\"$$(TRAVIS_BUILD_NUMBER)\"'"
+}
+
+DEFINES += LINUXDEPLOYQT_VERSION="'\"$(shell git describe --tags $(shell git rev-list --tags --skip=1 --max-count=1) --abbrev=0)\"'"