4.54 How to automatically build images needed for the latex file?

I put all my images needed for the document in an images/ folder below the main document folder. Using recusrive make, the document Makefile has this line at its top

DIRS = images 
 
include common.mk 
...
 

Then the Makefile in the images/ file looks like this

DIRS = 
 
include common.mk 
 
FILES := $(shell ls -1 *.pdf) 
#$(info $$FILES is [${FILES}]) 
TARGET = $(basename $(FILES)) 
#$(info $$TARGET is [${TARGET}]) 
 
all:: ${TARGET:=.svg} 
        @echo "Finished building [$?]" 
 
%.svg : %.pdf 
        prep $< 
 
.PHONY: clean 
clean :: 
        -rm -f ${TARGET:=.svg}
 

Where prep is my script I use to crop the images and generate SVG image from each. Here it is

>cat `which prep` 
#!/bin/bash 
set -u 
set -e 
set -o pipefail 
 
for file in $1; do 
    filename=${file%.*} 
    pdfcrop --margins 10 --clip "$filename.pdf" "$filename.pdf" 
    pdf2svg "$filename.pdf" "$filename.svg" 
#    pdftops -f 1 -l 1  -level3 -eps "$filename.pdf" 
done 
my_courses>
 

I use pdf file for the source of all the images. The above setup takes care of updating the images if one of them changes when compiling the latex file.