do not install the custom tty font on macos

due to problems with permissions this prevent installing on macos.
there is no tty on macos anyway, so this is not needed.

this resolves #365

Makefile.am

@@ -20,6 +20,8 @@ if OSX
     cava_CFLAGS += -DNORT
 else
     cava_LDFLAGS += -lrt
+    cava_font_dir = @FONT_DIR@
+    cava_font__DATA = cava.psf
 endif
 
 if ALSA
@@ -42,8 +44,6 @@ if NCURSES
     cava_SOURCES += output/terminal_ncurses.c
 endif
 
-cava_font_dir = @FONT_DIR@
-cava_font__DATA = cava.psf
 
 if !SYSTEM_LIBINIPARSER
     cava_LDADD = -liniparser