Add minimal metadata for a Tup build system. Tup will discover any file
named "Tupfile" in a the sub-directories where it is run. In this case a
tupfile defines the core name and invokes the "include_rules" directive,
which will include the Tup rules defined in parent directories. This
allows a parent repository with platform-specific build rules to host
this repository as a submodule. The sample cores may thus be ported to
new platforms without polluting the local makefiles. Naturally the
external build rules must be synchronized with the source code herein,
the tupfiles here only define TARGET_NAME so that they will never
contradict information contained in the makefiles.
A sample Tuprules.tup for a super-repository:
ifeq ($(TARGET_NAME),advanced_tests)
CFLAGS += -I../../libretro-common/include
SOURCES_C += libretro-test.c
endif
CFLAGS += -O3 -Wall -pedantic -std=gnu99
: foreach $(SOURCES_C) |> !libretro_cc |> {objs}
: {objs} |> !libretro_ld |> $(TARGET_NAME)_libretro.so
