nativesdk-rpm: adjust RPM_CONFIGDIR paths dynamically

While installing/extracting SDK to a non-default dir(not /opt),
run rpm failed:
$ python3 -c "import rpm"
|error: Unable to open /opt/windriver/wrlinux-graphics/20.31/sysroots/
x86_64-wrlinuxsdk-linux/usr/lib/rpm/rpmrc for reading: No such file or
directory.

This patch adds a flexible way to configure RPM_CONFIGDIR in SDK.

(From OE-Core rev: 5f16fd0bf774314c79572daf4ba7e4a8ae209ba1)

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/rpm/files/environment.d-rpm.sh

@@ -0,0 +1 @@
+export RPM_CONFIGDIR="$OECORE_NATIVE_SYSROOT/usr/lib/rpm"

meta/recipes-devtools/rpm/rpm_4.15.1.bb

@@ -25,6 +25,7 @@ LICENSE = "GPL-2.0"
 LIC_FILES_CHKSUM = "file://COPYING;md5=c0bf017c0fd1920e6158a333acabfd4a"
 
 SRC_URI = "git://github.com/rpm-software-management/rpm;branch=rpm-4.15.x \
+           file://environment.d-rpm.sh \
            file://0001-Do-not-add-an-unsatisfiable-dependency-when-building.patch \
            file://0001-Do-not-read-config-files-from-HOME.patch \
            file://0001-When-cross-installing-execute-package-scriptlets-wit.patch \
@@ -112,6 +113,9 @@ do_install_append_class-nativesdk() {
         done
 
         rm -rf ${D}/var
+
+        mkdir -p ${D}${SDKPATHNATIVE}/environment-setup.d
+        install -m 644 ${WORKDIR}/environment.d-rpm.sh ${D}${SDKPATHNATIVE}/environment-setup.d/rpm.sh
 }
 
 # Rpm's make install creates var/tmp which clashes with base-files packaging
@@ -129,6 +133,7 @@ do_install_append () {
 
 FILES_${PN} += "${libdir}/rpm-plugins/*.so \
                "
+FILES_${PN}_append_class-nativesdk = " ${SDKPATHNATIVE}/environment-setup.d/rpm.sh"
 
 FILES_${PN}-dev += "${libdir}/rpm-plugins/*.la \
                     "