py/py.mk: Make berkeley-db C-defs apply only to relevant source files.

Otherwise they can interfere (eg redefinition of "abort") with other source
files in a given uPy port.

py/py.mk

@@ -74,7 +74,7 @@ endif
 
 ifeq ($(MICROPY_PY_BTREE),1)
 BTREE_DIR = lib/berkeley-db-1.xx
-CFLAGS_MOD += -D__DBINTERFACE_PRIVATE=1 -Dmpool_error=printf -Dabort=abort_ -Dvirt_fd_t=mp_obj_t "-DVIRT_FD_T_HEADER=<py/obj.h>"
+BTREE_DEFS = -D__DBINTERFACE_PRIVATE=1 -Dmpool_error=printf -Dabort=abort_ -Dvirt_fd_t=mp_obj_t "-DVIRT_FD_T_HEADER=<py/obj.h>"
 INC += -I../$(BTREE_DIR)/PORT/include
 SRC_MOD += extmod/modbtree.c
 SRC_MOD += $(addprefix $(BTREE_DIR)/,\
@@ -95,7 +95,9 @@ mpool/mpool.c \
 	)
 CFLAGS_MOD += -DMICROPY_PY_BTREE=1
 # we need to suppress certain warnings to get berkeley-db to compile cleanly
-$(BUILD)/$(BTREE_DIR)/%.o: CFLAGS += -Wno-old-style-definition -Wno-sign-compare -Wno-unused-parameter
+# and we have separate BTREE_DEFS so the definitions don't interfere with other source code
+$(BUILD)/$(BTREE_DIR)/%.o: CFLAGS += -Wno-old-style-definition -Wno-sign-compare -Wno-unused-parameter $(BTREE_DEFS)
+$(BUILD)/extmod/modbtree.o: CFLAGS += $(BTREE_DEFS)
 endif
 
 # py object files