nrpe-4.1.3 fails to compile without ssl support

[dicksnippe]

Hello,

compiling nrpe-4.1.3 without ssl support (i.e. configure --disable-ssl) fails for nrpe-4.1.3:

In file included from ./nrpe.c:44:
../include/nrpe-ssl.h:47:50: error: unknown type name 'X509_STORE_CTX'
   47 | int ssl_verify_callback_common(int preverify_ok, X509_STORE_CTX * ctx, int is_invalid);
      |                                                  ^~~~~~~~~~~~~~
make[1]: *** [Makefile:50: nrpe] Error 1

And even if this were patched, e.g. by protecting ssl_verify_callback_common in include/nrpe-ssl.h with something like #ifdef HAVE_SSL the compile fails somewhere down the line.

This was not yet the case in nrpe-4.1.1 (don't know about nrpe-4.1.2, sorry)

kind regards,

[lgmu]

I've had another problem when compiling nrpe 4.1.3 on RHEL 10:

gcc -g -O2  -DHAVE_CONFIG_H -I ../include -I ./../include -c -o utils.o ./utils.c
In file included from ./utils.c:31:
./../include/common.h:36:12: fatal error: openssl/engine.h: No such file or directory
   36 | #  include <openssl/engine.h>
      |            ^~~~~~~~~~~~~~~~~~
compilation terminated.

I've fixed it by removing # include <openssl/engine.h> from ./include/common.h after running ./configure and then running make all

It seems like this has been removed in RHEL 10, I've found a similar problem here: codership/galera#663

Maybe this is also a leftover in the code and could also be removed here: https://github.com/NagiosEnterprises/nrpe/blob/master/include/common.h.in#L36