Fix version information, mk. 3

tools/linuxdeployqt/linuxdeployqt.pro

@@ -24,10 +24,13 @@ 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')\"'"
 
-isEmpty($(TRAVIS_BUILD_NUMBER)) {
+_BUILD_NUMBER = $$TRAVIS_BUILD_NUMBER
+
+isEmpty(_BUILD_NUMBER) {
     DEFINES += BUILD_NUMBER="'\"<local dev build>\"'"
 } else {
-    DEFINES += BUILD_NUMBER="'\"$(TRAVIS_BUILD_NUMBER)\"'"
+    message(Building on Travis CI build, build number $$_BUILD_NUMBER)
+    DEFINES += BUILD_NUMBER="'\"$$_BUILD_NUMBER\"'"
 }
 
 DEFINES += LINUXDEPLOYQT_VERSION="'\"$(shell git describe --tags $(shell git rev-list --tags --skip=1 --max-count=1) --abbrev=0)\"'"