meson: remove linkage of sdl to baum

Ever since commit 537fe2d63f744e7c96ff45b60d09486a81958e06 there
has been a 'linkage' to sdl for compiling baum.c. Originally it
had to do with including sdl cflags for any file including sdl
headers. There is no longer any such need for baum.c, but the
association has persisted in the make system, and with the switch
to meson it has now become a hard requirement, which now causes
chardev-baum.so to not be produced if sdl is not configured.
Remove this bogus linkage.

Signed-off-by: Bruce Rogers <brogers@suse.com>
Message-Id: <20200903152933.97838-1-brogers@suse.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/chardev/meson.build b/chardev/meson.build
index 27a9a28..54e88d0 100644
--- a/chardev/meson.build
+++ b/chardev/meson.build
@@ -36,9 +36,9 @@
 
 chardev_modules = {}
 
-if config_host.has_key('CONFIG_BRLAPI') and sdl.found()
+if config_host.has_key('CONFIG_BRLAPI')
   module_ss = ss.source_set()
-  module_ss.add(when: [sdl, brlapi], if_true: [files('baum.c'), pixman])
+  module_ss.add(when: [brlapi], if_true: [files('baum.c'), pixman])
   chardev_modules += { 'baum': module_ss }
 endif