We need to list the versioned shared library as one of the LIBS so that 
targets operating on all the libraries such as 'make install' enumerate
it.

--- zlib-1.2.3.4.dfsg.orig/Makefile.in
+++ zlib-1.2.3.4.dfsg/Makefile.in
@@ -34,7 +34,7 @@ STATICLIB=libz.a
 SHAREDLIB=libz.so
 SHAREDLIBV=libz.so.1.2.3.4
 SHAREDLIBM=libz.so.1
-LIBS=$(STATICLIB) $(SHAREDLIB)
+LIBS=$(STATICLIB) $(SHAREDLIB) $(SHAREDLIBV)
 
 AR=ar rc
 RANLIB=ranlib
