dependency handling oddity

[Joe Orton]

In the attached Makefile, a convenience library "libssl.la" is created,
which depends on a system library -lssl.  This works fine except if
libssl.la already exists in the cwd, in which case libtool drops the
dependency on -lssl.  Unexpected behaviour?

$ make clean
rm -rf .libs *.lo *.la
$ make libssl.la
...
/usr/bin/libtool --mode=link gcc -o libssl.la foo.lo -lssl
...
$ grep dependency_libs libssl.la
dependency_libs=' -lssl'
$ rm foo.lo && make libssl.la
...
/usr/bin/libtool --mode=link gcc -o libssl.la foo.lo -lssl
...
$ grep dependency_libs libssl.la
dependency_libs=' '

Makefile
Description: Text document