Dependency to generated list of source files

[daniel.steinmann]

For my project I would like to generate the list of source files before 
starting the compilation. Example:

srcs_file := srcs.txt
srcs = $(shell cat $(srcs_file) 2>/dev/null)
objs = $(srcs:%.c=%.o)

all : $(srcs_file) $(objs)

clean :
        rm -f $(srcs_file)
        rm -f $(srcs) $(objs)

$(srcs_file) :
        for f in foo.c bar.c; do touch $$f; echo $$f >> $@; done

%.o : %.c
        touch $@

The problem is, that only the second invocation of 'make' builds the targets 
specified in 'objs'. This is probably because during the first invocation the 
variable 'objs' has no value.

Is there a way to avoid two invocations of make?

Any help is appreciated. Regards,
Daniel