From c947c2529427fedea2b6d7b1dead8b61f6e8a28d Mon Sep 17 00:00:00 2001
From: David Lechner <david@pybricks.com>
Date: Mon, 18 Jul 2022 11:40:27 -0500
Subject: [PATCH] unix/Makefile: Only checkout libffi submodule when used.

This moves the libffi submodule variable modifier inside of the if
statement where it is actually used so that the submodule will only be
checked out if it is actually being used.

A new DEPLIBS variable is also introduced to prevent building the libffi
submodule when not needed.

Signed-off-by: David Lechner <david@pybricks.com>
---
 ports/unix/Makefile | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/ports/unix/Makefile b/ports/unix/Makefile
index 04d2242a27..3b339c3d3f 100644
--- a/ports/unix/Makefile
+++ b/ports/unix/Makefile
@@ -30,7 +30,7 @@ UNAME_S := $(shell uname -s)
 include $(TOP)/py/py.mk
 include $(TOP)/extmod/extmod.mk
 
-GIT_SUBMODULES += lib/berkeley-db-1.xx lib/libffi
+GIT_SUBMODULES += lib/berkeley-db-1.xx
 
 INC +=  -I.
 INC +=  -I$(TOP)
@@ -202,6 +202,9 @@ endif
 ifeq ($(MICROPY_PY_FFI),1)
 
 ifeq ($(MICROPY_STANDALONE),1)
+# Build libffi from source.
+GIT_SUBMODULES += lib/libffi
+DEPLIBS += libffi
 LIBFFI_CFLAGS_MOD := -I$(shell ls -1d $(BUILD)/lib/libffi/out/lib/libffi-*/include)
  ifeq ($(MICROPY_FORCE_32BIT),1)
   LIBFFI_LDFLAGS_MOD = $(BUILD)/lib/libffi/out/lib32/libffi.a
@@ -209,6 +212,7 @@ LIBFFI_CFLAGS_MOD := -I$(shell ls -1d $(BUILD)/lib/libffi/out/lib/libffi-*/inclu
   LIBFFI_LDFLAGS_MOD = $(BUILD)/lib/libffi/out/lib/libffi.a
  endif
 else
+# Use system version of libffi.
 LIBFFI_CFLAGS_MOD := $(shell pkg-config --cflags libffi)
 LIBFFI_LDFLAGS_MOD := $(shell pkg-config --libs libffi)
 endif
@@ -325,7 +329,7 @@ else
 CROSS_COMPILE_HOST =
 endif
 
-deplibs: libffi
+deplibs: $(DEPLIBS)
 
 libffi: $(BUILD)/lib/libffi/include/ffi.h