Pass the make's -j option to rpmbuild

For most people simply running "make autospec" or "make build", this
will have no effect. The RPM macro %{_smp_mflags} is predefined to be
the number of CPUs in your system anyway (output of getconf
_NPROCESSORS_ONLN).

But if you do have MAKEFLAGS set in your environment to your CPU
number (and you should), that will get passed to rpmbuild, which then
uses it during the build. And if you, like me, have it set to a
slightly higher number, RPM will use that too.

But if you run "make -jN autospec", then that N will be passed to the
build. This is especially important if you have something doing "make
-j1": RPM will be -j1 too! So instead of "make -j1", run "MAKEFLAGS= make"

Makefile.common

@@ -21,7 +21,8 @@ RPMS ?= $(LATEST_RPMS)
 WITH_SUDO = $(shell cmp /usr/bin/mock /usr/sbin/mock &> /dev/null && echo sudo )
 
 # MOCK_CONFIG_VAL is set in Makefile.shared
-MOCK ?= $(WITH_SUDO) /usr/bin/mock -r $(MOCK_CONFIG_VAL) $(MOCK_OPTS)
+MOCK_SMP_FLAGS=$(patsubst -j%, -D_smp_mflags\ -j%,$(filter -j%, $(MAKEFLAGS)))
+MOCK ?= $(WITH_SUDO) /usr/bin/mock -r $(MOCK_CONFIG_VAL) $(MOCK_SMP_FLAGS) $(MOCK_OPTS)
 
 ifneq ($(wildcard upstream),)
 __allsources := $(notdir $(strip $(shell cat upstream)))
@@ -172,7 +173,7 @@ autospec: preautospec-checks pullrebase localreponotice clean-old-content
 		--name $(PKG_NAME) \
 		--archives $(ARCHIVES) \
 		--mock-config $(MOCK_CONFIG_VAL) \
-		--mock-opts="$(MOCK_OPTS)" \
+		--mock-opts="$(MOCK_SMP_FLAGS) $(MOCK_OPTS)" \
 		$${SETVERSION:+ --version $${SETVERSION}} \
 		$${NON_INTERACTIVE:+ --non_interactive} \
 		$${SKIP_GIT:+ --skip-git} \