libtool seems to ignore -(all-)static

[Jan Engelhardt]

Despite choosing all kinds of -static* options for libtool,
it won't pick $old_library iff $installed=yes. Why is this?

I have produced the following minimal testcase. Using below's
libzz.la, I observe:

$ libtool --mode=link --tag=CXX g++ -o foo -static -all-static libzz.la
libtool: link: g++ -o foo  /usr/local/lib/libzz.so

I would have expected:

libtool: link: g++ -o foo  ${whatever}/libzz.a

----
# libzz.la - a libtool library file
# Generated by libtool (GNU libtool) 2.4.2
# Please DO NOT delete this file!
# It is necessary for linking the library.
dlname='libzz.so.0'
library_names='libzz.so.0.0.0 libzz.so.0.0 libzz.so.0 libzz.so'
old_library='libzz.a'
inherited_linker_flags=''
dependency_libs=''
weak_library_names=''
current=0
age=0
revision=0
installed=yes
shouldnotlink=no
dlopen=''
dlpreopen=''
libdir='/usr/local/lib'