escape backslashes (or don't use them at all, resp.)

doc/doc.pri

@@ -7,8 +7,8 @@ equals(QMAKE_DIR_SEP, /) {   # unix, mingw+msys
     # The lack of spaces in front of the && is necessary!
     QDOC = set SRCDIR=$$PWD&& set OUTDIR=$$OUT_PWD/doc/html&& $$QDOC_BIN
 } else {   # nmake
-    QDOC = set SRCDIR=$$PWD $$escape_expand(\n\t) \
-           set OUTDIR=$$OUT_PWD/doc/html $$escape_expand(\n\t) \
+    QDOC = set SRCDIR=$$PWD $$escape_expand(\\n\\t) \
+           set OUTDIR=$$OUT_PWD/doc/html $$escape_expand(\\n\\t) \
            $$QDOC_BIN
 }
 

qtcreator.pro

 #version check qt
-contains(QT_VERSION, ^4\.[0-6]\..*) {
+contains(QT_VERSION, ^4\\.[0-6]\\..*) {
     message("Cannot build Qt Creator with Qt version $${QT_VERSION}.")
     error("Use at least Qt 4.7.")
 }

src/tools/qtcdebugger/qtcdebugger.pro

@@ -4,4 +4,4 @@ TARGET = qtcdebugger
 TEMPLATE = app
 SOURCES += main.cpp
 
-DESTDIR=..\..\..\bin
+DESTDIR=../../../bin