build: Move clients libexec_PROGRAMS under BUILD_CLIENTS conditional

All the libexec programs are only built when BUILD_CLIENTS is true,
so we can just assign libexec_PROGRAMS under the condition.  This lets us
drop most of the variable assignments and simplify it a bit.

https://bugs.freedesktop.org/show_bug.cgi?id=72812

tests/Makefile.am

@@ -114,7 +114,7 @@ event_weston_LDADD = libtest-client.la
 button_weston_SOURCES = button-test.c
 button_weston_LDADD = libtest-client.la
 
-text_weston_SOURCES = text-test.c ../clients/text-protocol.c
+text_weston_SOURCES = text-test.c text-protocol.c
 text_weston_LDADD = libtest-client.la
 
 subsurface_weston_SOURCES = subsurface-test.c
@@ -154,7 +154,9 @@ EXTRA_DIST = weston-tests-env
 BUILT_SOURCES =					\
 	wayland-test-protocol.c			\
 	wayland-test-server-protocol.h		\
-	wayland-test-client-protocol.h
+	wayland-test-client-protocol.h		\
+	text-protocol.c				\
+	text-client-protocol.h
 
 CLEANFILES = $(BUILT_SOURCES)
 

tests/text-test.c

@@ -24,7 +24,7 @@
 #include <stdio.h>
 #include <linux/input.h>
 #include "weston-test-client-helper.h"
-#include "../clients/text-client-protocol.h"
+#include "text-client-protocol.h"
 
 struct text_input_state {
 	int activated;