QCGExternalLibs: Getting independent of dpkg

Basically unextracting the deb-file with ar and tar as dpkg would do, too.
This is more handy if you are in a non-Debian environment or very minimal one.

Signed-off-by: Thomas Karl Pietrowski <thopiekar@gmail.com>

QGCExternalLibs.pri

@@ -240,7 +240,8 @@ contains (DEFINES, DISABLE_AIRMAP) {
             rm -rf $${AIRMAP_PLATFORM_SDK_PATH} && \
             mkdir -p "$${AIRMAP_PLATFORM_SDK_PATH}/linux/$${AIRMAP_QT_PATH}" && \
             mkdir -p "$${AIRMAP_PLATFORM_SDK_PATH}/include/airmap" && \
-            wget -q -O "$${OUT_PWD}/$${AIRMAP_PLATFORM_SDK_FILENAME}" "$${AIRMAP_PLATFORM_SDK_URL}" && dpkg -x "$${AIRMAP_PLATFORM_SDK_FILENAME} $${AIRMAP_PLATFORM_SDK_PATH}/" && \
+            wget -q -O "$${OUT_PWD}/$${AIRMAP_PLATFORM_SDK_FILENAME}" "$${AIRMAP_PLATFORM_SDK_URL}" && \
+            ar p "$${AIRMAP_PLATFORM_SDK_FILENAME}" data.tar.gz | tar xvz -C "$${AIRMAP_PLATFORM_SDK_PATH}/" --strip-components=1 && \
             mv -u "$${AIRMAP_PLATFORM_SDK_PATH}/$${AIRMAP_PLATFORM_SDK_INSTALL_PREFIX}/lib/x86_64-linux-gnu/*" "$${AIRMAP_PLATFORM_SDK_PATH}/linux/$${AIRMAP_QT_PATH}/" && \
             mv -u "$${AIRMAP_PLATFORM_SDK_PATH}/$${AIRMAP_PLATFORM_SDK_INSTALL_PREFIX}/include/airmap/*" "$${AIRMAP_PLATFORM_SDK_PATH}/include/airmap/" && \
             rm -rf "$${AIRMAP_PLATFORM_SDK_PATH}/$${AIRMAP_PLATFORM_SDK_INSTALL_PREFIX}" && \