OpenRCT2: enforce 64-bit long double

This is a workaround for IBM long double not allowing for
constant expressions.

srcpkgs/OpenRCT2/template

@@ -52,6 +52,13 @@ if [ "$XBPS_TARGET_ENDIAN" = "be" ]; then
 	broken="not yet implemented"
 fi
 
+case "$XBPS_TARGET_MACHINE" in
+        ppc*)
+                CFLAGS+=" -mlong-double-64"
+                CXXFLAGS+=" -mlong-double-64"
+                ;;
+esac
+
 if [ "$CROSS_BUILD" ]; then
 	hostmakedepends+=" OpenRCT2"
 	# for icu mass-rebuild