RISCOS: Don't list RISC OS as a POSIX platform

backends/platform/sdl/posix/posix-main.cpp

@@ -22,7 +22,7 @@
 
 #include "common/scummsys.h"
 
-#if defined(POSIX) && !defined(MACOSX) && !defined(SAMSUNGTV) && !defined(MAEMO) && !defined(WEBOS) && !defined(LINUXMOTO) && !defined(GPH_DEVICE) && !defined(GP2X) && !defined(DINGUX) && !defined(OPENPANDORA) && !defined(PLAYSTATION3) && !defined(PSP2) && !defined(ANDROIDSDL) && !defined(RISCOS)
+#if defined(POSIX) && !defined(MACOSX) && !defined(SAMSUNGTV) && !defined(MAEMO) && !defined(WEBOS) && !defined(LINUXMOTO) && !defined(GPH_DEVICE) && !defined(GP2X) && !defined(DINGUX) && !defined(OPENPANDORA) && !defined(PLAYSTATION3) && !defined(PSP2) && !defined(ANDROIDSDL)
 
 #include "backends/platform/sdl/posix/posix.h"
 #include "backends/plugins/sdl/sdl-provider.h"

configure

@@ -2839,8 +2839,6 @@ if test -n "$_host"; then
 		arm-linux|arm*-linux-gnueabi|arm-*-linux)
 			;;
 		arm-*riscos)
-			_seq_midi=no
-			_timidity=no
 			_opengl_mode=none
 			_build_hq_scalers=no
 			# toolchain binaries prefixed by host
@@ -3601,10 +3599,10 @@ esac
 #
 echo_n "Checking if host is POSIX compliant... "
 case $_host_os in
-	amigaos* | cygwin* | dreamcast | ds | gamecube | mingw* | n64 | ps2 | ps3 | psp2 | psp | wii | wince)
+	amigaos* | cygwin* | dreamcast | ds | gamecube | mingw* | n64 | ps2 | ps3 | psp2 | psp | riscos | wii | wince)
 		_posix=no
 		;;
-	3ds | android | androidsdl | beos* | bsd* | darwin* | freebsd* | gnu* | gph-linux | haiku* | hpux* | iphone | ios7 | irix*| k*bsd*-gnu* | linux* | maemo | mint* | netbsd* | openbsd* | riscos | solaris* | sunos* | uclinux* | webos)
+	3ds | android | androidsdl | beos* | bsd* | darwin* | freebsd* | gnu* | gph-linux | haiku* | hpux* | iphone | ios7 | irix*| k*bsd*-gnu* | linux* | maemo | mint* | netbsd* | openbsd* | solaris* | sunos* | uclinux* | webos)
 		_posix=yes
 		;;
 	os2-emx*)