qt4: fix QMAKE_QT_CONFIG being overwritten with empty value

QMAKE_QT_CONFIG is set by the linux-oe-g++ mkspec but it is overwritten
with an empty value read from .qmake.cache. Avoid this by first checking
if the value from .qmake.cache is not empty before assigning it to
QMAKE_QT_CONFIG.

This allows variables from qconfig.pri such as QT_ARCH, QT_CONFIG,
QT_VERSION, etc. to be queried by qmake projects.

(From OE-Core rev: 5330905749828ea8befdee559c180754ac506b75)

Signed-off-by: Jonathan Liu <net147@gmail.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/meta/recipes-qt/qt4/qt4-4.8.4.inc b/meta/recipes-qt/qt4/qt4-4.8.4.inc
index ce12b1e52b..e87daccf5a 100644
--- a/meta/recipes-qt/qt4/qt4-4.8.4.inc
+++ b/meta/recipes-qt/qt4/qt4-4.8.4.inc
@@ -25,6 +25,7 @@ SRC_URI = "http://releases.qt-project.org/qt4/source/qt-everywhere-opensource-sr
            file://0023-qtnetwork-blacklist-two-more-certificates.patch \
            file://0024-Change-all-shmget-calls-to-user-only-memory.patch \
            file://0025-Remove-unnecessary-typedef-found-by-gcc4-8.patch \
+           file://0026-Don-t-overwrite-QMAKE_QT_CONFIG-with-empty-value.patch \
            file://g++.conf \
            file://linux.conf \
            "