dependency -> prerequisite in manual

[Vladimir E. Ignatov]

Hello!

Maybe you forget replace:

"dependency file" -> "prerequisite"   
"multiple dependencies" -> "multiple prerequisities"   

here:

---------------------------------- ( from Make 3.79 manual )
When using GNU make, relying on `VPATH' to find the source file will work in
the case where there is a single dependency file, since the make automatic
variable `$<' will represent the source file wherever it is. (Many versions
of make set `$<' only in implicit rules.) A Makefile target like 

foo.o : bar.c
        $(CC) -I. -I$(srcdir) $(CFLAGS) -c bar.c -o foo.o

should instead be written as 

foo.o : bar.c
        $(CC) -I. -I$(srcdir) $(CFLAGS) -c $< -o $@

in order to allow `VPATH' to work correctly. When the target has multiple
dependencies, using an explicit `$(srcdir)' is the easiest way to make the
rule work well. For example, the target above for `foo.1' is best written
as: 

foo.1 : foo.man sedscript
        sed -e $(srcdir)/sedscript $(srcdir)/foo.man > $@
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