[openwrt/openwrt] build/image: warn if missing qemu-img for VDI/VMDK

[LEDE Commits]

aparcar pushed a commit to openwrt/openwrt.git, branch master:
https://git.openwrt.org/ca289e322d87bd14271de84b25291c2979f96781

commit ca289e322d87bd14271de84b25291c2979f96781
Author: Paul Spooren <mail at aparcar.org>
AuthorDate: Wed Dec 30 09:08:17 2020 -1000

    build/image: warn if missing qemu-img for VDI/VMDK
    
    Currently `qemu-img` is used to convert raw x86 images to VDI and VMDK
    images, used for virtual machines.
    
    Having `qemu-img` in tree requires us to maintain an ancient version of
    `qemu-utils`, which recently required extra work to compile with newer
    compiler version.
    
    This commit prints a warning message in case `qemu-img` is missing.
    
    As a next step the in-tree version of `qemu-img` can be removed.
    
    Signed-off-by: Paul Spooren <mail at aparcar.org>
---
 include/image-commands.mk | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/image-commands.mk b/include/image-commands.mk
index 979eafb157..3beec80c8b 100644
--- a/include/image-commands.mk
+++ b/include/image-commands.mk
@@ -291,8 +291,12 @@ endef
 # Convert a raw image into a $1 type image.
 # E.g. | qemu-image vdi
 define Build/qemu-image
-	qemu-img convert -f raw -O $1 $@ $@.new
-	@mv $@.new $@
+	if command -v qemu-img; then \
+		qemu-img convert -f raw -O $1 $@ $@.new; \
+		mv $@.new $@; \
+	else \
+		echo "WARNING: Install qemu-img to create VDI/VMDK images" >&2; exit 1; \
+	fi
 endef
 
 define Build/qsdk-ipq-factory-nand