openssl: basic dbg package

[xnox]

Add a basic manual dbg package for openssl.

Install source code into /usr/src/${{package.name}} (maybe needs a
pipeline like that).

Use -g to create debug symbols and file-prefix-map to encode all
source code references in the debug symbols to that destination.

Use split/debug as the first subpackage to detach all debug.

Note build-ids are not set by split/debug pipeline, meaning these
debug symbols are not suitable to upload into debuginfod server. See
https://sourceware.org/elfutils/Debuginfod.html

But this will do for now, installing openssl-dbg allows gdb to just
work. This is needed to stream-line security lab assesments, but also
to debug OpenSSL features and bugs.

Sample gdb session:

Reading symbols from openssl...
Reading symbols from /usr/lib/debug//usr/bin/openssl.debug...
(gdb) break main
warning: could not convert 'main' from the host encoding (ISO-8859-1) to UTF-32.
This normally should not happen, please file a bug report.
Breakpoint 1 at 0x499a0: file apps/openssl.c, line 236.
(gdb) run
Starting program: /usr/bin/openssl 
warning: Error disabling address space randomization: Operation not permitted
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/libthread_db.so.1".

Breakpoint 1, main (argc=1, argv=0x7ffd74888238) at apps/openssl.c:236
236	{
(gdb) l
231	
232	static char *help_argv[] = { "help", NULL };
233	static char *version_argv[] = { "version", NULL };
234	
235	int main(int argc, char *argv[])
236	{
237	    FUNCTION f, *fp;
238	    LHASH_OF(FUNCTION) *prog = NULL;
239	    char *pname;
240	    const char *fname;
(gdb) 

[smoser]

TIL about split/debug.

Thanks.