fix build for --disable-clients --enable-simple-clients

Simple clients were relying on AM_CFLAGS and AM_CPPFLAGS set for
toytoolkit clients. With toytoolkit clients disabled, the build fails
with missing wayland-client.h.

Move AM_CFLAGS and AM_CPPFLAGS outside of conditional sections, since
they are meant to be global settings.

Let simple clients override AM_CPPFLAGS with their own
SIMPLE_CLIENT_CFLAGS, which the configure script already sets up for us,
but was unused until now.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>

clients/Makefile.am

@@ -11,6 +11,12 @@ libexec_PROGRAMS =				\
 	$(tablet_shell)				\
 	$(screenshooter)
 
+AM_CFLAGS = $(GCC_CFLAGS)
+AM_CPPFLAGS =					\
+	-DDATADIR='"$(datadir)"'		\
+	-DBINDIR='"$(bindir)"'			\
+	$(CLIENT_CFLAGS) $(CAIRO_EGL_CFLAGS)
+
 if BUILD_SIMPLE_CLIENTS
 simple_clients_programs =			\
 	simple-egl				\
@@ -18,12 +24,15 @@ simple_clients_programs =			\
 	simple-touch
 
 simple_egl_SOURCES = simple-egl.c
+simple_egl_CPPFLAGS = $(SIMPLE_CLIENT_CFLAGS)
 simple_egl_LDADD = $(SIMPLE_CLIENT_LIBS) -lm
 
 simple_shm_SOURCES = simple-shm.c
+simple_shm_CPPFLAGS = $(SIMPLE_CLIENT_CFLAGS)
 simple_shm_LDADD = $(SIMPLE_CLIENT_LIBS)
 
 simple_touch_SOURCES = simple-touch.c
+simple_touch_CPPFLAGS = $(SIMPLE_CLIENT_CFLAGS)
 simple_touch_LDADD = $(SIMPLE_CLIENT_LIBS)
 endif
 
@@ -46,12 +55,6 @@ screenshooter = weston-screenshooter
 
 noinst_LIBRARIES = libtoytoolkit.a
 
-AM_CFLAGS = $(GCC_CFLAGS)
-AM_CPPFLAGS =					\
-	-DDATADIR='"$(datadir)"'		\
-	-DBINDIR='"$(bindir)"'			\
-	$(CLIENT_CFLAGS) $(CAIRO_EGL_CFLAGS)
-
 libtoytoolkit_a_SOURCES =			\
 	window.c				\
 	window.h				\