+Edit the makefile.mk (or Makefile, if using nmake) and change the values
+of INST_DRV and INST_TOP. You can also enable various build
+flags.
+
+Beginning with version 5.005, there is experimental support for building
+a perl interpreter that supports the Perl Object abstraction (courtesy
+ActiveState Tool Corp.) PERL_OBJECT uses C++, and the binaries are
+therefore incompatible with the regular C build. However, the
+PERL_OBJECT build does provide something called the C-API, for linking
+it with extensions that won't compile under PERL_OBJECT. Using the C_API
+is typically requested through:
+
+ perl Makefile.PL CAPI=TRUE
+
+PERL_OBJECT requires VC++ 5.0 (Service Pack 3 recommended) or later. It
+is not yet supported under GCC. WARNING: Binaries built with
+PERL_OBJECT enabled are B<not> compatible with binaries built without.
+Perl installs PERL_OBJECT binaries under a distinct architecture name,
+so they B<can> coexist, though.
+
+Beginning with version 5.005, there is experimental support for building
+a perl interpreter that is capable of native threading. Binaries built
+with thread support enabled are also incompatible with the vanilla C
+build. WARNING: Binaries built with threads enabled are B<not> compatible
+with binaries built without. Perl installs threads enabled binaries under
+a distinct architecture name, so they B<can> coexist, though.
+
+At the present time, you cannot enable both threading and PERL_OBJECT.
+You can get only one of them in a Perl interpreter.
+
+If you have either the source or a library that contains des_fcrypt(),
+enable the appropriate option in the makefile. des_fcrypt() is not
+bundled with the distribution due to US Government restrictions
+on the export of cryptographic software. Nevertheless, this routine
+is part of the "libdes" library (written by Eric Young) which is widely
+available worldwide, usually along with SSLeay (for example:
+"ftp://fractal.mta.ca/pub/crypto/SSLeay/DES/"). Set CRYPT_SRC to the
+name of the file that implements des_fcrypt(). Alternatively, if
+you have built a library that contains des_fcrypt(), you can set
+CRYPT_LIB to point to the library name. The location above contains
+many versions of the "libdes" library, all with slightly different
+implementations of des_fcrypt(). Older versions have a single,
+self-contained file (fcrypt.c) that implements crypt(), so they may be
+easier to use. A patch against the fcrypt.c found in libdes-3.06 is
+in des_fcrypt.patch.
+
+Perl will also build without des_fcrypt(), but the crypt() builtin will
+fail at run time.