Bug#943706: opencv: delete static build dir to save lots of space during build

[Samuel Thibault]

Control: reopen -1
Control: retitle -1 opencv: avoid building gigabytes of unused example binaries

Hello,

> du -hs obj-x86_64-linux-gnu-static
> 46G     obj-x86_64-linux-gnu-static

> this is just used during dh_install place, can we just remove it after
> copying files into debian/tmp/ directory?

Mmm. That huge space is actually coming mostly from the few hundreds of
100-MB statically-linked examples... which we don't even install. Do we
really need to enable -DBUILD_EXAMPLES=ON, actually?  At least, we could
avoid uselessly building the unused static version with the attached
change. That'll reduce disk usage from tens of gigabytes down to a few
gigabytes, and probably reduce the build time a lot as well.

Samuel
-------------- next part --------------
--- debian/rules.original	2020-01-01 19:27:07.000000000 +0000
+++ debian/rules	2020-01-05 19:30:09.000000000 +0000
@@ -52,7 +58,6 @@
 CMAKE_FLAGS = \
 	-GNinja \
 	-DANT_EXECUTABLE=/usr/bin/ant \
-	-DBUILD_EXAMPLES=ON	\
 	-DBUILD_JAVA=ON \
 	-DBUILD_PROTOBUF=OFF \
 	-DBUILD_TESTS=ON \
@@ -123,6 +127,7 @@
 	# dynamicly linked
 	dh_auto_configure -B $(BUILDDIR) \
 		-- $(CMAKE_FLAGS) \
+		-DBUILD_EXAMPLES=ON \
 		-DCMAKE_SHARED_LINKER_FLAGS_RELEASE="$(LDFLAGS)" \
 		-DBUILD_SHARED_LIBS=ON -DBUILD_DOCS=ON
 	# statically linked