QtBase (remainder): use printf-style qWarning/qDebug where possible (I)

The printf-style version of QDebug expands to a lot less code than the
std::ostream-style version. Of course, you pay in type safety (but
compilers warn about it these days), you cannot stream complex Qt
types and streaming QStrings is awkward, but in many cases you
actually improve on readability.

But the main reason is that something that's not supposed to be
executed under normal operation has no business bloating executable
code size.

This is not an attempt at converting all qWarnings() to printf-style,
only the low-hanging fruit.

In this first part, replace
   qWarning() << ""
with
   qWarning("...").

Had to fix broken qImDebug() definition. Instead of defining it as
a nullary macro in the QT_NO_DEBUG case and as a variadic macro in
the other, define it in both cases, as is customary, as a non-function
macro so that overload selection works without requiring variadic
macro support of the compiler.

Saves e.g. ~250b in text size in QtPrintSupport on optimized GCC 5.3
AMD64 builds.

Change-Id: Ie30fe2f7942115d5dbf99fff1750ae0d477c379f
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/src/plugins/platforms/xcb/qxcbkeyboard.cpp b/src/plugins/platforms/xcb/qxcbkeyboard.cpp
index 4de7716703..a16e24061c 100644
--- a/src/plugins/platforms/xcb/qxcbkeyboard.cpp
+++ b/src/plugins/platforms/xcb/qxcbkeyboard.cpp
@@ -676,13 +676,13 @@ void QXcbKeyboard::printKeymapError(const char *error) const
 {
     qWarning() << error;
     if (xkb_context) {
-        qWarning() << "Current XKB configuration data search paths are: ";
+        qWarning("Current XKB configuration data search paths are: ");
         for (unsigned int i = 0; i < xkb_context_num_include_paths(xkb_context); ++i)
             qWarning() << xkb_context_include_path_get(xkb_context, i);
     }
-    qWarning() << "Use QT_XKB_CONFIG_ROOT environmental variable to provide an additional search path, "
-                  "add ':' as separator to provide several search paths and/or make sure that XKB configuration data "
-                  "directory contains recent enough contents, to update please see http://cgit.freedesktop.org/xkeyboard-config/ .";
+    qWarning("Use QT_XKB_CONFIG_ROOT environmental variable to provide an additional search path, "
+             "add ':' as separator to provide several search paths and/or make sure that XKB configuration data "
+             "directory contains recent enough contents, to update please see http://cgit.freedesktop.org/xkeyboard-config/ .");
 }
 
 void QXcbKeyboard::updateKeymap()