worked out core build process

.gitignore

@@ -7,4 +7,8 @@ releases/
 *.o
 *.so
 *.elf
-*.dtb
+*.dtb
+
+# thanks I hate it
+src/minarch/cores/*
+!src/minarch/cores/makefile

makefile

@@ -32,7 +32,7 @@ sys:
 	cd ./src/minui && make
 
 cores:
-	echo "TODO: cores"
+	cd ./src/minarch/cores && make
 
 tools:
 	cd ./src/clock && make
@@ -59,6 +59,18 @@ bundle:
 	cp ./src/minarch/minarch.elf ./build/SYSTEM/rg35xx/bin
 	cp ./src/minui/minui.elf ./build/SYSTEM/rg35xx/paks/MinUI.pak
 	cp ./src/clock/clock.elf ./build/EXTRAS/Tools/rg35xx/Clock.pak
+	
+	# stock cores
+	cp ./src/minarch/cores/fceumm_libretro.so ./build/SYSTEM/rg35xx/cores
+	cp ./src/minarch/cores/gambatte_libretro.so ./build/SYSTEM/rg35xx/cores
+	cp ./src/minarch/cores/gpsp_libretro.so ./build/SYSTEM/rg35xx/cores
+	cp ./src/minarch/cores/pcsx_rearmed_libretro.so ./build/SYSTEM/rg35xx/cores
+	cp ./src/minarch/cores/picodrive_libretro.so ./build/EXTRAS/Emus/rg35xx/PKM.pak
+	cp ./src/minarch/cores/snes9x2005_plus_libretro.so ./build/SYSTEM/rg35xx/cores
+
+	# extras
+	cp ./src/minarch/cores/beetle-vb_libretro.so ./build/EXTRAS/Emus/rg35xx/VB.pak
+	cp ./src/minarch/cores/pokemini_libretro.so ./build/SYSTEM/rg35xx/cores
 	cp ./third-party/DinguxCommander/output/DinguxCommander ./build/EXTRAS/Tools/rg35xx/Files.pak
 	cp -R ./third-party/DinguxCommander/res ./build/EXTRAS/Tools/rg35xx/Files.pak/
 	

src/minarch/cores/makefile

@@ -0,0 +1,77 @@
+# this logic was broken out from picoarch's all-in-one makefile
+
+CORES = fceumm gambatte gpsp pcsx_rearmed picodrive pokemini snes9x2005_plus
+CORES+= beetle-vb
+
+###############################
+
+# optional core vars
+# *_REPO=
+# *_HASH=
+# *_CORE=
+# *_FLAGS=
+# *_MAKEFILE=
+# *_BUILD_PATH=
+
+beetle-vb_REPO = https://github.com/libretro/beetle-vb-libretro
+beetle-vb_CORE = mednafen_vb_libretro.so
+
+fceumm_REPO = https://github.com/libretro/libretro-fceumm
+
+gambatte_REPO = https://github.com/libretro/gambatte-libretro
+
+pcsx_rearmed_MAKEFILE = Makefile.libretro
+
+picodrive_REPO = https://github.com/irixxxx/picodrive
+picodrive_MAKEFILE = Makefile.libretro
+
+pokemini_REPO = https://github.com/libretro/PokeMini
+pokemini_MAKEFILE = Makefile.libretro
+
+snes9x2005_plus_REPO = https://github.com/libretro/snes9x2005
+snes9x2005_plus_FLAGS = USE_BLARGG_APU=1
+
+###############################
+
+PATCH = git apply
+PROCS = -j4
+
+###############################
+
+define TEMPLATE=
+
+$1_REPO ?= https://github.com/libretro/$(1)
+$1_MAKE ?= make $(and $($1_MAKEFILE),-f $($1_MAKEFILE)) platform=$(UNION_PLATFORM) $($(1)_FLAGS)
+$1_BUILD_PATH ?= $(1)
+
+$(1):
+	mkdir -p cores
+	cd cores && git clone $(if $($1_HASH),,--depth 1) --recursive $$($(1)_REPO) $(1)
+	$(if $($1_HASH),cd $$($1_BUILD_PATH) && git checkout $($1_HASH) && echo $($1_HASH),)
+
+$(1)/.patched: $(1)
+	(test ! -f patches/$(1).patch) || (test -f $(1)/.patched) || (cd $(1) && $(PATCH) -p1 < ../../patches/$(1).patch && touch .patched && true)
+
+$(1)_libretro.so: $(1)/.patched
+	cd $$($1_BUILD_PATH) && $$($1_MAKE) $(PROCS)
+	mv $$($1_BUILD_PATH)/$(if $($(1)_CORE),$($(1)_CORE),$(1)_libretro.so) $(1)_libretro.so
+
+clone-$(1): $(1)
+	
+patch-$(1): $(1)/.patched
+
+clean-$(1):
+	test ! -d $(1) || cd $$($1_BUILD_PATH) && $$($1_MAKE) clean
+	rm -rf $(1)_libretro.so
+
+$(1): $(1)_libretro.so
+
+endef
+
+###############################
+
+all: cores
+
+$(foreach CORE,$(CORES),$(eval $(call TEMPLATE,$(CORE))))
+
+cores: $(foreach CORE,$(CORES),$(CORE)_libretro.so)