diff --git a/libretro-build-common.sh b/libretro-build-common.sh
index af424ac2..4accae77 100755
--- a/libretro-build-common.sh
+++ b/libretro-build-common.sh
@@ -184,7 +184,9 @@ build_libretro_generic_makefile() {
 #
 # $core_build_subdir		Subdir of the makefile (if any)
 # $core_build_makefile	Name of the makefile (if not {GNUm,m,M}akefile)
+# $core_build_args		Extra arguments to make
 # $core_build_platform	Usually some variant of $FORMAT_COMPILER_TARGET
+# $core_build_cores		A list of cores produced by the builds
 build_makefile() {
 	[ -n "$core_build_subdir" ] && core_build_subdir="/$core_build_subdir"
 
@@ -209,14 +211,22 @@ build_makefile() {
 	if [ -d "$build_dir" ]; then
 		echo_cmd "cd \"$build_dir\""
 
+		$core_build_configure
+
 		if [ -z "$NOCLEAN" ]; then
-			echo_cmd "$make_cmdline clean"
+			$core_build_preclean
+			echo_cmd "$make_cmdline $core_build_args clean"
 		fi
 		make_cmdline="$make_cmdline $COMPILER"
-		echo_cmd "$make_cmdline"
 
-		# TODO: Make this a separate stage rule
-		copy_core_to_dist $1
+		$core_build_prebuild
+		echo_cmd "$make_cmdline $core_build_args"
+
+		# TODO: Make this a separate stage/package rule
+		$core_build_prepkg
+		for a in $core_build_cores; do
+			copy_core_to_dist ${core_build_products:+$core_build_products/}$a $a
+		done
 	else
 		echo "$1 not fetched, skipping ..."
 	fi
@@ -262,13 +272,20 @@ libretro_build_core() {
 
 	case "$core_build_rule" in
 		generic_makefile)
+			core_build_configure="libretro_${1}_build_configure"
+			core_build_preclean="libretro_${1}_build_preclean"
+			core_build_prebuild="libretro_${1}_build_prebuild"
+			core_build_prepkg="libretro_${1}_build_prepkg"
 			eval "core_build_makefile=\$libretro_${1}_build_makefile"
 			eval "core_build_subdir=\$libretro_${1}_build_subdir"
+			eval "core_build_args=\$libretro_${1}_build_args"
 
 			# TODO: Really, clean this up...
 			eval "core_build_platform=\$libretro_${1}_build_platform"
 			core_build_platform="${core_build_platform:-$FORMAT_COMPILER_TARGET}$opengl_type"
 
+			eval "core_build_cores=\${libretro_${1}_build_cores:-$1}"
+			eval "core_build_products=\$libretro_${1}_build_products"
 			echo "Building ${1}..."
 			build_makefile $1
 			;;
@@ -407,288 +424,9 @@ create_dist_dir() {
 create_dist_dir
 
 
-########## LEGACY RULES
-# TODO: Safe to delete these when scripts no longer reference them
-
-build_libretro_2048() {
-	libretro_build_core 2048
-}
-build_libretro_3dengine() {
-	libretro_build_core 3dengine
-}
-build_libretro_4do() {
-	libretro_build_core 4do
-}
-build_libretro_beetle_gba() {
-	libretro_build_core mednafen_gba
-}
-build_libretro_beetle_lynx() {
-	libretro_build_core mednafen_lynx
-}
-build_libretro_beetle_ngp() {
-	libretro_build_core mednafen_ngp
-}
-build_libretro_beetle_pce_fast() {
-	libretro_build_core mednafen_pce_fast
-}
-build_libretro_beetle_pcfx() {
-	libretro_build_core mednafen_pcfx
-}
-build_libretro_beetle_psx() {
-	libretro_build_core mednafen_psx
-}
-build_libretro_beetle_snes() {
-	libretro_build_core mednafen_snes
-}
-build_libretro_beetle_supergrafx() {
-	libretro_build_core mednafen_supergrafx
-}
-build_libretro_beetle_vb() {
-	libretro_build_core mednafen_vb
-}
-build_libretro_beetle_wswan() {
-	libretro_build_core mednafen_wsawn
-}
-build_libretro_bluemsx() {
-	libretro_build_core bluemsx
-}
-build_libretro_catsfc() {
-	libretro_build_core catsfc
-}
-build_libretro_desmume() {
-	libretro_build_core desmume
-}
-build_libretro_dinothawr() {
-	libretro_build_core dinothawr
-}
-build_libretro_dosbox() {
-	libretro_build_core dosbox
-}
-build_libretro_fb_alpha() {
-	libretro_build_core fb_alpha
-}
-build_libretro_fceumm() {
-	libretro_build_core fceumm
-}
-build_libretro_ffmpeg() {
-	libretro_build_core ffmpeg
-}
-build_libretro_fmsx() {
-	libretro_build_core fmsx
-}
-build_libretro_fuse() {
-	libretro_build_core fuse
-}
-build_libretro_gambatte() {
-	libretro_build_core gambatte
-}
-build_libretro_genesis_plus_gx() {
-	libretro_build_core genesis_plus_gx
-}
-build_libretro_gpsp() {
-	libretro_build_core gpsp
-}
-build_libretro_handy() {
-	libretro_build_core handy
-}
-build_libretro_hatari() {
-	libretro_build_core hatari
-}
-build_libretro_mame078() {
-	libretro_build_core mame078
-}
-build_libretro_mednafen_psx() {
-	libretro_build_core mednafen_psx
-}
-build_libretro_meteor() {
-	libretro_build_core meteor
-}
-build_libretro_nestopia() {
-	libretro_build_core nestopia
-}
-build_libretro_nx() {
-	libretro_build_core nxengine
-}
-build_libretro_o2em() {
-	libretro_build_core o2em
-}
-build_libretro_picodrive() {
-	libretro_build_core picodrive
-}
-build_libretro_ppsspp() {
-	libretro_build_core ppsspp
-}
-build_libretro_prboom() {
-	libretro_build_core prboom
-}
-build_libretro_prosystem() {
-	libretro_build_core prosystem
-}
-build_libretro_quicknes() {
-	libretro_build_core quicknes
-}
-build_libretro_scummvm() {
-	libretro_build_core scummvm
-}
-build_libretro_snes9x() {
-	libretro_build_core snes9x
-}
-build_libretro_snes9x_next() {
-	libretro_build_core snes9x_next
-}
-build_libretro_stella() {
-	libretro_build_core stella
-}
-build_libretro_stonesoup() {
-	libretro_build_core stonesoup
-}
-build_libretro_tgbdual() {
-	libretro_build_core tgbdual
-}
-build_libretro_tyrquake() {
-	libretro_build_core tyrquake
-}
-build_libretro_vba_next() {
-	libretro_build_core vba_next
-}
-build_libretro_vbam() {
-	libretro_build_core vbam
-}
-build_libretro_vecx() {
-	libretro_build_core vecx
-}
-build_libretro_virtualjaguar() {
-	libretro_build_core virtualjaguar
-}
-build_libretro_yabause() {
-	libretro_build_core yabause
-}
-build_libretro_gw() {
-	libretro_build_core gw
-}
-build_libretro_lutro() {
-	libretro_build_core lutro
-}
-
 ########## LEGACY RULES
 # TODO: Port these to modern rules
 
-build_libretro_bnes() {
-	build_dir="$WORKDIR/libretro-bnes"
-
-	if build_should_skip bnes "$build_dir"; then
-		echo "Core bnes is already built, skipping..."
-		return
-	fi
-
-	if [ -d "$build_dir" ]; then
-		echo '=== Building bNES ==='
-		echo_cmd "cd \"$build_dir\""
-
-		mkdir -p obj
-		if [ -z "$NOCLEAN" ]; then
-			echo_cmd "$MAKE -f Makefile \"-j$JOBS\" clean" || die 'Failed to clean bNES'
-		fi
-		echo_cmd "$MAKE -f Makefile $COMPILER \"-j$JOBS\" compiler=\"${CXX11}\"" || die 'Failed to build bNES'
-		copy_core_to_dist "bnes"
-		build_save_revision $? "bnes"
-	else
-		echo 'bNES not fetched, skipping ...'
-	fi
-}
-
-build_libretro_bsnes_modern() {
-	build_dir="$WORKDIR/libretro-$1"
-	if [ -d "$build_dir" ]; then
-		echo "=== Building $1 ==="
-		echo_cmd "cd \"$build_dir\""
-		
-		if [ -z "$NOCLEAN" ]; then
-			echo_cmd "rm -f obj/*.{o,\"$FORMAT_EXT\"}"
-			echo_cmd "rm -f out/*.{o,\"$FORMAT_EXT\"}"
-		fi
-
-		cmdline="$MAKE target=libretro -j$JOBS"
-		cmdline="$cmdline platform=\"$FORMAT_COMPILER_TARGET\""
-		cmdline="$cmdline compiler=\"$CXX11\""
-		ret=0
-		for a in accuracy balanced performance; do
-			echo_cmd "$cmdline profile=$a"
-			copy_core_to_dist "out/${1}_$a" "${1}_$a"
-			[ $ret -eq 0 ] || break
-		done
-
-		return $ret
-	else
-		echo "$1 not fetched, skipping ..."
-	fi
-}
-
-build_libretro_bsnes() {
-	if build_should_skip bsnes "$WORKDIR/libretro-bsnes"; then
-		echo "Core bsnes is already built, skipping..."
-		return
-	fi
-
-	build_libretro_bsnes_modern "bsnes"
-	build_save_revision $? bsnes
-}
-
-build_libretro_bsnes_cplusplus98() {
-	CORENAME="bsnes_cplusplus98"
-	build_dir="$WORKDIR/libretro-$CORENAME"
-
-	if build_should_skip $CORENAME "$build_dir"; then
-		echo "Core $CORENAME is already built, skipping..."
-		return
-	fi
-
-	if [ -d "$build_dir" ]; then
-		echo "=== Building $CORENAME ==="
-		echo_cmd "cd \"$build_dir\""
-
-		if [ -z "$NOCLEAN" ]; then
-			# byuu's "make clean" doesn't
-			echo_cmd "rm -f obj/*.{o,\"$FORMAT_EXT\"}"
-			echo_cmd "rm -f out/*.{o,\"$FORMAT_EXT\"}"
-		fi
-
-		echo_cmd "$MAKE platform=\"$FORMAT_COMPILER_TARGET\" $COMPILER \"-j$JOBS\""
-		copy_core_to_dist "out/$CORENAME" "$CORENAME"
-		build_save_revision $? $CORENAME
-	else
-		echo "$CORENAME not fetched, skipping ..."
-	fi
-}
-
-build_libretro_bsnes_mercury() {
-	if build_should_skip bsnes_mercury "$WORKDIR/libretro-bsnes"; then
-		echo "Core bsnes_mercury is already built, skipping..."
-		return
-	fi
-
-	build_libretro_bsnes_modern "bsnes_mercury"
-	build_save_revision $? bsnes_mercury
-}
-
-
-build_libretro_emux() {
-	if build_should_skip emux "$WORKDIR/libretro-emux"; then
-		echo "Cores for emux are already built, skipping..."
-		return
-	fi
-
-	build_libretro_generic_makefile "emux" "libretro" "Makefile" $FORMAT_COMPILER_TARGET 1
-
-	copy_core_to_dist "emux_chip8"
-	copy_core_to_dist "emux_gb"
-	copy_core_to_dist "emux_nes"
-	copy_core_to_dist "emux_sms"
-
-	# TODO: Check for more than emux_sms here...
-	build_save_revision $? "emux"
-}
-
 build_libretro_mupen64() {
 	if check_opengl; then
 		build_dir="$WORKDIR/libretro-mupen64plus"
@@ -701,8 +439,6 @@ build_libretro_mupen64() {
 		if [ -d "$build_dir" ]; then
 			echo_cmd "cd \"$build_dir\""
 
-			mkdir -p obj
-
 			if iscpu_x86_64 $ARCH; then
 				dynarec="WITH_DYNAREC=x86_64"
 			elif iscpu_x86 $ARCH; then
diff --git a/rules.d/core-rules.sh b/rules.d/core-rules.sh
index 09a5c16f..dca92e14 100644
--- a/rules.d/core-rules.sh
+++ b/rules.d/core-rules.sh
@@ -3,8 +3,9 @@
 register_core "bsnes" -theos_ios -ngc -ps3 -psp1 -qnx -wii
 libretro_bsnes_name="bsnes/higan"
 libretro_bsnes_git_url="https://github.com/libretro/bsnes-libretro.git"
-libretro_bsnes_build_rule=legacy
-libretro_bsnes_build_legacy=build_libretro_bsnes
+libretro_bsnes_build_args="compiler=\"${CXX11}\""
+libretro_bsnes_build_products="out"
+libretro_bsnes_build_cores="bsnes_accuracy bsnes_balanced bsnes_performance"
 
 register_core "snes9x" -ngc -ps3 -psp1 -wii
 libretro_snes9x_name="SNES9x"
@@ -53,8 +54,7 @@ libretro_cap32_build_makefile="Makefile"
 register_core "bnes" -ios -theos_ios -ngc -ps3 -psp1 -qnx -wii
 libretro_bnes_name="bnes/higan"
 libretro_bnes_git_url="https://github.com/libretro/bnes-libretro.git"
-libretro_bnes_build_rule=legacy
-libretro_bnes_build_legacy=build_libretro_bnes
+libretro_bnes_build_args="compiler=\"${CXX11}\""
 
 register_core "fceumm"
 libretro_fceumm_name="FCEUmm"
@@ -200,14 +200,14 @@ libretro_ffmpeg_build_opengl="optional"
 register_core "bsnes_cplusplus98" -theos_ios -ngc -ps3 -psp1 -wii
 libretro_bsnes_cplusplus98_name="bsnes C++98 (v0.85)"
 libretro_bsnes_cplusplus98_git_url="https://github.com/libretro/bsnes-libretro-cplusplus98.git"
-libretro_bsnes_cplusplus98_build_rule=legacy
-libretro_bsnes_cplusplus98_build_legacy=build_libretro_bsnes_cplusplus98
+libretro_bsnes_cplusplus98_build_products="out"
 
 register_core "bsnes_mercury" -theos_ios -ngc -ps3 -psp1 -qnx -wii
 libretro_bsnes_mercury_name="bsnes-mercury"
 libretro_bsnes_mercury_git_url="https://github.com/libretro/bsnes-mercury.git"
-libretro_bsnes_mercury_build_rule=legacy
-libretro_bsnes_mercury_build_legacy=build_libretro_bsnes_mercury
+libretro_bsnes_mercury_build_args="compiler=\"${CXX11}\""
+libretro_bsnes_mercury_build_products="out"
+libretro_bsnes_mercury_build_cores="bsnes_mercury_accuracy bsnes_mercury_balanced bsnes_mercury_performance"
 
 register_core "picodrive" -theos_ios -ngc -ps3 -wii
 libretro_picodrive_name="Picodrive"
@@ -309,8 +309,8 @@ libretro_gpsp_git_url="https://github.com/libretro/gpsp.git"
 register_core "emux" -theos_ios -ngc -ps3 -psp1 -qnx -wii
 libretro_emux_name="Emux"
 libretro_emux_git_url="https://github.com/libretro/emux.git"
-libretro_emux_build_rule=legacy
-libretro_emux_build_legacy=build_libretro_emux
+libretro_emux_build_subdir=libretro
+libretro_emux_build_cores="emux_chip8 emux_gb emux_nes emux_sms"
 
 register_core "fuse" -theos_ios -ngc -ps3 -psp1 -qnx -wii
 libretro_fuse_name="Fuse"
@@ -394,12 +394,22 @@ libretro_lutro_game_of_life_git_url="https://github.com/libretro/lutro-game-of-l
 # build_makefile			Name of makefile
 #								If unset, GNU make has rules for default makefile names
 #
+# build_subdir				The subdir containing the makefile, if any
+#
+# build_args				Any extra arguments to pass to make
+#
 # build_platform			Set to override the default platform
 #								(e.g., $FORMAT_COMPILER_TARGET_ALT)
 #
 # build_opengl				Set to "optional" to use OpenGL/GLES if available
 #								Set to "yes" if the core requires it
 #
+# build_cores				String containing the core(s) produced
+#								Defaults to "<core>"
+#
+# build_products			Directory build products are located in
+#								bsnes puts cores in "out" for some reason
+#
 # Example:
 #
 #	libretro_dinothawr_git_url="https://github.com/libretro/Dinothawr.git"