sdlapp: Enable compilation of most apps/games

Removes `#ifdef`s in many places to just have `HAVE_TOUCHSCREEN` be the
input fall back, as is already tentatively the case in the code.

Solitaire was the only app excluded since there aren’t enough buttons
for it mapped in the SDL layer.

Change-Id: I62450b7110b86c8037a121e96cd2e46754be79a3

apps/plugins/calculator.c

@@ -557,7 +557,7 @@ F3: equal to "="
 #define CALCULATOR_CALC  BUTTON_MENU
 #define CALCULATOR_CLEAR BUTTON_USER
 
-#else
+#elif !defined(HAVE_TOUCHSCREEN)
 #error No keymap defined!
 #endif
 
@@ -583,6 +583,9 @@ F3: equal to "="
 #ifndef CALCULATOR_CLEAR
 #define CALCULATOR_CLEAR          BUTTON_TOPRIGHT
 #endif
+#ifndef CALCULATOR_QUIT
+#define CALCULATOR_QUIT           BUTTON_TOPLEFT
+#endif
 
 #include "lib/pluginlib_touchscreen.h"
 static struct ts_raster calc_raster = { X_0_POS, Y_1_POS,