MT#63051 debian: Improve makefile coding style

Add spaces around variables assignments to make it clear that these are
make variables and equal signs to not bind to multiple variables.

Split multivalue variables into one value per line to make it easier to
sort and modify entries without creating unrelated diff damage.

Change-Id: I87532c3446ae61cc5003ab0714f6b36f89429b56

debian/rules

@@ -2,21 +2,37 @@
 # -*- makefile -*-
 
 # Uncomment this to turn on verbose mode.
-export DH_VERBOSE=1
+export DH_VERBOSE = 1
 
-EXCLUDED_MODULES=conf_auth examples/db_announce fast_ack gateway ivr mailbox mp3 pin_collect twit webconference
-
-EXCLUDED_DSM_MODULES=mod_aws mod_py
-EXCLUDED_DSM_PY_MODULES=mod_aws mod_py
+EXCLUDED_MODULES = \
+	conf_auth \
+	examples/db_announce \
+	fast_ack \
+	gateway \
+	ivr \
+	mailbox \
+	mp3 \
+	pin_collect \
+	twit \
+	webconference \
+	# EOL
+EXCLUDED_DSM_MODULES = \
+	mod_aws \
+	mod_py \
+	# EOL
+EXCLUDED_DSM_PY_MODULES = \
+	mod_aws \
+	mod_py \
+	# EOL
 
 export DEB_CPPFLAGS_APPEND = -DHAVE_XMLRPCPP_SSL
 
-export APP_NAME=ngcp-sems
-export SYSTEM_SAMPLECLOCK_RATE=48000LL
-export LONG_DEBUG_MESSAGE=yes
-export USE_THREADPOOL=yes
-export USE_SPANDSP=yes
-export PYTHON_VERSION=3
+export APP_NAME = ngcp-sems
+export PYTHON_VERSION = 3
+export SYSTEM_SAMPLECLOCK_RATE = 48000LL
+export LONG_DEBUG_MESSAGE = yes
+export USE_THREADPOOL = yes
+export USE_SPANDSP = yes
 
 
 # Enable parallel builds for overrides.
@@ -31,10 +47,10 @@ endif
 
 override_dh_auto_build:
 	$(MAKE) \
-	cfg_target=/etc/$(APP_NAME)/ prefix=/usr \
-	exclude_app_modules="$(EXCLUDED_MODULES)" \
-	exclude_dsm_modules="$(EXCLUDED_DSM_MODULES)" \
-	DESTDIR=$(CURDIR)/debian/$(APP_NAME)
+		cfg_target=/etc/$(APP_NAME)/ prefix=/usr \
+		exclude_app_modules="$(EXCLUDED_MODULES)" \
+		exclude_dsm_modules="$(EXCLUDED_DSM_MODULES)" \
+		DESTDIR=$(CURDIR)/debian/$(APP_NAME)
 
 override_dh_auto_install:
 	$(MAKE) -C core/ install \