simplify host_build logic again

qt_tool handles bootstrapping fully automatically.

This reverts commit 0fc040ef70,
and adds some more.

Change-Id: Icffcf7f487dbf660678c7ee622f94b1063fef7e3
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>

src/qmldevtools/qmldevtools.pro

@@ -1,12 +1,6 @@
 option(host_build)
 TARGET     = QtQmlDevTools
-
-force_bootstrap {
-    QT = bootstrap-private
-} else {
-    QT = core
-}
-
+QT         = core
 CONFIG += static no_module_headers internal_module
 
 MODULE_INCLUDES = \

tools/qmlimportscanner/qmlimportscanner.pro

@@ -1,12 +1,6 @@
 option(host_build)
 
-force_bootstrap {
-    QT = bootstrap-private
-} else {
-    QT = core
-}
-
-QT += qmldevtools-private
+QT = core qmldevtools-private
 DEFINES += QT_NO_CAST_TO_ASCII QT_NO_CAST_FROM_ASCII
 
 SOURCES += main.cpp

tools/qmlmin/qmlmin.pro

@@ -1,13 +1,5 @@
 option(host_build)
-
-force_bootstrap {
-    QT = bootstrap-private
-} else {
-    QT = core
-}
-
-QT += qmldevtools-private
-
+QT       = core qmldevtools-private
 SOURCES += main.cpp
 
 load(qt_tool)