packaging: parallelize libqt-jami deb package build

Change-Id: Ie938153fd4581e6007c4c2c65b82649c56c31e4c

packaging/rules/debian-qt/rules

@@ -3,10 +3,17 @@
 
 # export DH_VERBOSE = 1
 
+# Number of CPUS
+NO_CPUS=$(shell nproc)
+ifeq ($(NO_CPUS),0)
+NO_CPUS=1
+endif
+
 %:
 	dh $@
 
 override_dh_auto_configure:
+	MAKEFLAGS="-j$(NO_CPUS) V=1" \
 		./configure \
 			-opensource \
 			-confirm-license \