Make strong function defninition replace a weak one

common.mk

@@ -134,9 +134,15 @@ $$($(1)_OBJ_DIR)%.o: $$($(1)_REAL_ROOT)%.S $$($(1)_MAKEFILE) $(wildcard $(ROOT)*
 	$$($(1)_CC_BASE) -c $$< -o $$@
 	$$($(1)_CC_BASE) -MM -MT $$@ -MF $$(@:.o=.d) $$<
 
-# the component is shown to depend on both obj and source files so we get a meaningful error message
-# for missing explicitly named source files
-$$($(1)_AR): $$($(1)_OBJ_FILES) $$($(1)_SRC_FILES)
+$(1)_AR_IN_FILES = $$($(1)_OBJ_FILES)
+
+# the component is shown to depend on both obj and source files so we get 
+# a meaningful error message for missing explicitly named source files
+ifeq ($(INCLUDE_SRC_IN_AR),1)
+   $(1)_AR_IN_FILES += $$($(1)_SRC_FILES)
+endif
+
+$$($(1)_AR): $$($(1)_AR_IN_FILES)
 	$(vecho) "AR $$@"
 	$(Q) mkdir -p $$(dir $$@)
 	$(Q) $(AR) cru $$@ $$^

extras/stdin_uart_interrupt/component.mk

@@ -4,10 +4,12 @@
 # for 'usage' as this module is a drop-in replacement for the original polled
 # version of reading from the UART.
 
-INC_DIRS += $(ROOT)extras/stdin_uart_interrupt
+INC_DIRS += $(stdin_uart_interrupt_ROOT)
 
 # args for passing into compile rule generation
-extras/stdin_uart_interrupt_INC_DIR =  $(ROOT)extras/stdin_uart_interrupt
-extras/stdin_uart_interrupt_SRC_DIR =  $(ROOT)extras/stdin_uart_interrupt
+stdin_uart_interrupt_SRC_DIR = $(stdin_uart_interrupt_ROOT)
 
-$(eval $(call component_compile_rules,extras/stdin_uart_interrupt))
+INCLUDE_SRC_IN_AR = 0
+EXTRA_LDFLAGS = -Wl,--whole-archive $(stdin_uart_interrupt_AR) -Wl,--no-whole-archive
+
+$(eval $(call component_compile_rules,stdin_uart_interrupt))

parameters.mk

@@ -42,6 +42,9 @@ PRINTF_SCANF_FLOAT_SUPPORT ?= 1
 
 FLAVOR ?= release # or debug
 
+# Include source files into a static library. It improves error messages.
+INCLUDE_SRC_IN_AR ?= 1
+
 # Compiler names, etc. assume gdb
 CROSS ?= xtensa-lx106-elf-