fix(Build): Allow Users to Give Absolute Paths to SRCS (#666)

Libraries/CMSIS/Device/Maxim/GCC/gcc.mk

@@ -36,6 +36,12 @@ ifeq "$(BUILD_DIR)" ""
 BUILD_DIR=$(CURDIR)/build
 endif
 
+# Make sure VPATH has the location of any absolute paths given to SRCS
+# This allows users to specify SRCS += /absolute/path/to/file.c to add a single file to the build
+# without also having to add VPATH += /absolute/path/to
+# This is necessary because we create our object file definitions with OBJS_NOPATH.
+VPATH += $(sort $(abspath $(dir $(SRCS))))
+
 # Create output object file names
 SRCS_NOPATH := $(foreach NAME,$(SRCS),$(basename $(notdir $(NAME))).c)
 BINS_NOPATH := $(foreach NAME,$(BINS),$(basename $(notdir $(NAME))).bin)
@@ -507,4 +513,4 @@ $(BUILD_DIR)/project_defines.h: mkbuildir
 	@echo "// This is a generated file that's used to detect definitions that have been set by the compiler and build system." > $@
 	@$(CC) -E -P -dD $(BUILD_DIR)/_empty_tmp_file.c $(CFLAGS) >> $@
 	@rm $(BUILD_DIR)/_empty_tmp_file.c
-	@rm _empty_tmp_file.d
+	@rm _empty_tmp_file.d

Libraries/CMSIS/Device/Maxim/GCC/gcc_riscv.mk

@@ -36,6 +36,12 @@ ifeq "$(BUILD_DIR)" ""
 BUILD_DIR=$(CURDIR)/buildrv
 endif
 
+# Make sure VPATH has the location of any absolute paths given to SRCS
+# This allows users to specify SRCS += /absolute/path/to/file.c to add a single file to the build
+# without also having to add VPATH += /absolute/path/to
+# This is necessary because we create our object file definitions with OBJS_NOPATH.
+VPATH += $(sort $(abspath $(dir $(SRCS))))
+
 # Create output object file names
 SRCS_NOPATH := $(foreach NAME,$(SRCS),$(basename $(notdir $(NAME))).c)
 OBJS_NOPATH := $(SRCS_NOPATH:.c=.o)
@@ -464,4 +470,4 @@ $(BUILD_DIR)/project_defines.h: mkbuildir
 	@echo "// This is a generated file that's used to detect definitions that have been set by the compiler and build system." > $@
 	@$(CC) -E -P -dD $(BUILD_DIR)/_empty_tmp_file.c $(CFLAGS) >> $@
 	@rm $(BUILD_DIR)/_empty_tmp_file.c
-	@rm _empty_tmp_file.d
+	@rm _empty_tmp_file.d