[RFC 10/15] sbuild: Introduce environment variables export API

[Anton Mikanovich <amikan@ilbers.de>]

In case there is no ability to pass variables through template
mechanism we need to keep fallback API to migrate from bare export.
Using it with optee-os-stm32mp15x recipe as example.

Signed-off-by: Anton Mikanovich <amikan@ilbers.de>
---
 .../optee-os/optee-os-stm32mp15x_3.11.0.bb          |  2 +-
 meta/classes/sbuild.bbclass                         | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/meta-isar/recipes-bsp/optee-os/optee-os-stm32mp15x_3.11.0.bb b/meta-isar/recipes-bsp/optee-os/optee-os-stm32mp15x_3.11.0.bb
index 0fa2005..19aa763 100644
--- a/meta-isar/recipes-bsp/optee-os/optee-os-stm32mp15x_3.11.0.bb
+++ b/meta-isar/recipes-bsp/optee-os/optee-os-stm32mp15x_3.11.0.bb
@@ -21,5 +21,5 @@ OPTEE_BINARIES = "tee-header_v2.stm32 tee-pageable_v2.stm32 tee-pager_v2.stm32"
 # Set version manually to PV, the tarball does not contain any hint.
 # Alternative: pull from git and add git as build dependency.
 dpkg_runbuild_prepend() {
-    export TEE_IMPL_VERSION=${PV}
+    sbuild_export TEE_IMPL_VERSION=${PV}
 }
diff --git a/meta/classes/sbuild.bbclass b/meta/classes/sbuild.bbclass
index ed2d0cf..cc7db66 100644
--- a/meta/classes/sbuild.bbclass
+++ b/meta/classes/sbuild.bbclass
@@ -15,3 +15,16 @@ python __anonymous() {
 
 SBUILD_CHROOT ?= "${DEBDISTRONAME}-${@os.getlogin()}-${DISTRO}-${SBUILD_HOST_ARCH}"
 SBUILD_CHROOT_RW ?= "${DEBDISTRONAME}-${@os.getlogin()}-${DISTRO}-${SBUILD_HOST_ARCH}-rw"
+
+sbuild_export() {
+    SBUILD_CONFIG="${WORKDIR}/sbuild.conf"
+    VAR_LINE="'${1%%=*}' => '${1#*=}',"
+    if [ -s "${SBUILD_CONFIG}" ]; then
+        sed -i -e "\$i\\" -e "${VAR_LINE}" ${SBUILD_CONFIG}
+    else
+        echo "\$build_environment = {" > ${SBUILD_CONFIG}
+        echo "${VAR_LINE}" >> ${SBUILD_CONFIG}
+        echo "};" >> ${SBUILD_CONFIG}
+    fi
+    export SBUILD_CONFIG="${SBUILD_CONFIG}"
+}
-- 
2.25.1