MICROPY_USE_READLINE: Selects link lib, so should be defined in mpconfigport.mk

This change allows to build unix version without libreadline installed.

unix/Makefile

@@ -20,6 +20,12 @@ else
     LDFLAGS = $(LDFLAGS_MOD) -lm -Wl,-Map=$@.map,--cref
  endif
 
+ifeq ($(MICROPY_USE_READLINE),1)
+CFLAGS_MOD += -DMICROPY_USE_READLINE=1
+LDFLAGS_MOD += -lreadline
+# the following is needed for BSD
+#LDFLAGS_MOD += -ltermcap
+endif
 ifeq ($(MICROPY_MOD_TIME),1)
 CFLAGS_MOD += -DMICROPY_MOD_TIME=1
 SRC_MOD += time.c
@@ -48,9 +54,6 @@ SRC_C = \
 	$(SRC_MOD)
 
 OBJ = $(PY_O) $(addprefix $(BUILD)/, $(SRC_C:.c=.o))
-LIB = -lreadline
-# the following is needed for BSD
-#LIB += -ltermcap
 
 include ../py/mkrules.mk
 

unix/mpconfigport.h

@@ -1,10 +1,5 @@
 // options to control how Micro Python is built
 
-// Linking with GNU readline causes binary to be licensed under GPL
-#ifndef MICROPY_USE_READLINE
-#define MICROPY_USE_READLINE        (1)
-#endif
-
 #define MICROPY_EMIT_X64            (1)
 #define MICROPY_EMIT_THUMB          (0)
 #define MICROPY_EMIT_INLINE_THUMB   (0)

unix/mpconfigport.mk

@@ -1,4 +1,7 @@
-# Enable/disable modules to be included in interpreter
+# Enable/disable modules and 3rd-party libs to be included in interpreter
+
+# Linking with GNU readline causes binary to be licensed under GPL
+MICROPY_USE_READLINE = 1
 
 # Subset of CPython time module
 MICROPY_MOD_TIME = 1