Use an out-of-source build in CI

Author: mszabo-wikia

ci/ubuntu-24.04-noble/debian/rules

@@ -9,7 +9,7 @@ include /usr/share/dpkg/buildflags.mk
 	dh $@ --buildsystem=cmake --parallel
 
 override_dh_auto_configure:
-	dh_auto_configure -- \
+	dh_auto_configure -B_build -- \
 	-Wno-dev \
 	-DCMAKE_INSTALL_PREFIX=/opt/hhvm/$(DEB_VERSION_UPSTREAM) \
 	-DMYSQL_UNIX_SOCK_ADDR=/var/run/mysqld/mysqld.sock \
@@ -24,9 +24,9 @@ override_dh_auto_configure:
 	-DENABLE_EXTENSION_IMAGICK=Off
 
 override_dh_auto_build:
-	dh_auto_build --parallel -- bundled_folly
-	dh_auto_build --no-parallel -- hack hack_rust_ffi_bridge hhbc_ast_cbindgen hack_dune || dh_auto_build --no-parallel -- hack hack_rust_ffi_bridge hhbc_ast_cbindgen hack_dune
-	dh_auto_build --parallel
+	dh_auto_build -B_build --parallel -- bundled_folly
+	dh_auto_build -B_build --no-parallel -- hack hack_rust_ffi_bridge hhbc_ast_cbindgen hack_dune || dh_auto_build -B_build --no-parallel -- hack hack_rust_ffi_bridge hhbc_ast_cbindgen hack_dune
+	dh_auto_build -B_build --parallel
 
 override_dh_strip:
 	dh_strip --dbg-package=hhvm-nightly-dbg