Wildcard usage in make file - makefile

Question

I currently have a build system based on a makefile that was originally auto-generated. I've made some changes over time for various functions. Each subdirectory in the project has a separate makefile (subdir.mk). However, each instance of subdir.mk explicitly lists the files in that subdirectory. I'd like to modify the files to do a wildcard build of all files in the directory, so that the files don't have to be updated if new files are added. I've copied one current file below. Any suggestions on how (or if) I can modify these files to do wildcard builds? I'm not a make expert (altho if I live through my current project I'd like to become one). Thanks.
################################################################################
# Automatically-generated file. Do not edit!
################################################################################
# Add inputs and outputs from these tool invocations to the build variables
C_SRCS += \
../Src/Tasks/BankWriteTask.c \
../Src/Tasks/CommTask.c \
../Src/Tasks/SrvTask.c \
../Src/Tasks/WatchdogTask.c
OBJS += \
./Src/Tasks/BankWriteTask.o \
./Src/Tasks/CommTask.o \
./Src/Tasks/SrvTask.o \
./Src/Tasks/WatchdogTask.o
C_DEPS += \
./Src/Tasks/BankWriteTask.d \
./Src/Tasks/CommTask.d \
./Src/Tasks/SrvTask.d \
./Src/Tasks/WatchdogTask.d
# Each subdirectory must supply rules for building sources it contributes
Src/Tasks/%.o: ../Src/Tasks/%.c
arm-atollic-eabi-gcc -c -mthumb -mcpu=cortex-m3 -std=gnu11 -D__weak=__attribute__((weak)) -D__packed=__attribute__((__packed__)) -DUSE_HAL_DRIVER -DSTM32L152xE -DCONFIG_DEBUG -DCONFIG_RELEASE=1 -I..\Config -I..\Inc -I..\Inc\Sys -I..\Inc\StmHal -I..\Inc\Driver -I..\Inc\Lib -I..\Inc\Business -I..\Inc\Tasks -I..\Drivers\CMSIS\Include -I..\Drivers\CMSIS\Device\ST\STM32L1xx\Include -I..\Drivers\STM32L1xx_HAL_Driver\Inc -I..\Drivers\STM32L1xx_HAL_Driver\Inc\Legacy -I..\Middlewares\Third_Party\FreeRTOS\Source\include -I..\Middlewares\Third_Party\FreeRTOS\Source\CMSIS_RTOS -I..\Middlewares\Third_Party\FreeRTOS\Source\portable\GCC\ARM_CM3 -I..\Middlewares\Third_Party\FreeRTOS-Plus\Source\FreeRTOS-Plus-CLI -I..\Middlewares\ST\STM32_Cryptographic\Inc -I..\Middlewares\ST\STM32_Cryptographic\Inc\HASH\SHA256 -I..\Middlewares\Third_Party\TraceRecorder\include -I..\Middlewares\Third_Party\TraceRecorder\streamports\Jlink_RTT -I..\Middlewares\Third_Party\TraceRecorder\streamports\Jlink_RTT\include -I../Inc -I../Drivers/STM32L1xx_HAL_Driver/Inc -O0 -ffunction-sections -fdata-sections -g -fstack-usage -Wall -MMD -MP -MF"$(#:%.o=%.d)" -MT"$(#)" -specs=nano.specs -o "$#" "$<"

Answer 1

First notice that there is a lot of redundancy in these lists of files:
C_SRCS += \
../Src/Tasks/BankWriteTask.c \
../Src/Tasks/CommTask.c \
../Src/Tasks/SrvTask.c \
../Src/Tasks/WatchdogTask.c
OBJS += \
./Src/Tasks/BankWriteTask.o \
./Src/Tasks/CommTask.o \
./Src/Tasks/SrvTask.o \
./Src/Tasks/WatchdogTask.o
C_DEPS += \
./Src/Tasks/BankWriteTask.d \
./Src/Tasks/CommTask.d \
./Src/Tasks/SrvTask.d \
./Src/Tasks/WatchdogTask.d
which you can reduce with the Make function patsubst:
NEW_C_SRCS := \
../Src/Tasks/BankWriteTask.c \
../Src/Tasks/CommTask.c \
../Src/Tasks/SrvTask.c \
../Src/Tasks/WatchdogTask.c
C_SRCS += $(NEW_C_SRCS)
OBJS += $(patsubst ../%.c,./%.o,$(NEW_C_SRCS))
C_DEPS += $(patsubst ../%.c,./%.d,$(NEW_C_SRCS))
And if the four files listed in C_SRCS are the only ".c" files in ../Src/, instead of typing them into the makefile by hand you can have Make find them automatically with the wildcard function:
NEW_C_SRCS := $(wildcard ../Src/Tasks/*.c)
That said, wildcard-building can work in a tightly-controlled source tree like the one you seem to be using, but it can cause headaches otherwise; modifying one line in a makefile when you add or remove a source file is not much work.