pick_best_scape() is now always included (even when building with NOSVG)

Was failing to compile on Haiku for Luc (apparently building with
no SVG support), since I started using that function outside of
SVG-related places.

Also, to continue being able to compile on Linux with no SVG support --
 * Always use SDL_TRUE & SDL_FALSE, not TRUE & FALSE
 * Always link tuxpaint with "-lm"

Finally, verbose version info ("tuxpaint --verbose-version") now states which
SVG build (new RSVG or old Cairo)

Makefile

@@ -4,7 +4,7 @@
 # Various contributors (see AUTHORS.txt)
 # https://tuxpaint.org/
 
-# June 14, 2002 - May 1, 2023
+# June 14, 2002 - May 9, 2023
 
 
 # The version number, for release:
@@ -1181,7 +1181,7 @@ tuxpaint:	obj/tuxpaint.o obj/i18n.o obj/im.o obj/cursor.o obj/pixels.o \
 	@echo "...Linking Tux Paint..."
 	$(CC) $(CFLAGS) $(LDFLAGS) $(DEBUG_FLAGS) $(SDL_CFLAGS) $(FRIBIDI_CFLAGS) $(DEFS) $(ARCH_DEFS) \
 		-o tuxpaint $^ \
-		$(SDL_LIBS) $(SVG_LIB) $(ARCH_LINKS)
+		$(SDL_LIBS) $(SVG_LIB) $(ARCH_LINKS) -lm
 	@$(RAD_CMD)
 	@$(RSRC_CMD)
 	@$(MIMESET_CMD)