kconfig: refactor Qt package checks for building qconf

Currently, the necessary package checks for building qconf is
surrounded by ifeq ($(MAKECMDGOALS),xconfig) ... endif.
Then, Make will restart when .tmp_qtcheck is generated.

To simplify the Makefile, move the scripting to a separate file,
and use filechk.  The shell script is executed everytime xconfig
is run, but it is not a costly script.

In the old code, 'pkg-config --exists' only checked Qt5Core / QtCore,
but the set of necessary packages should be checked.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>

scripts/kconfig/qconf-cfg.sh

@@ -0,0 +1,25 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+PKG="Qt5Core Qt5Gui Qt5Widgets"
+PKG2="QtCore QtGui"
+
+if pkg-config --exists $PKG; then
+	echo cflags=\"-std=c++11 -fPIC $(pkg-config --cflags Qt5Core Qt5Gui Qt5Widgets)\"
+	echo libs=\"$(pkg-config --libs $PKG)\"
+	echo moc=\"$(pkg-config --variable=host_bins Qt5Core)/moc\"
+	exit 0
+fi
+
+if pkg-config --exists $PKG2; then
+	echo cflags=\"$(pkg-config --cflags $PKG2)\"
+	echo libs=\"$(pkg-config --libs $PKG2)\"
+	echo moc=\"$(pkg-config --variable=moc_location QtCore)\"
+	exit 0
+fi
+
+echo >&2 "*"
+echo >&2 "* Could not find Qt via pkg-config."
+echo >&2 "* Please install either Qt 4.8 or 5.x. and make sure it's in PKG_CONFIG_PATH"
+echo >&2 "*"
+exit 1