patch 9.0.2180: POSIX function name in exarg causes issues

Problem:  POSIX function name in exarg struct causes issues
          on OpenVMS
Solution: Rename getline member in exarg struct to ea_getline,
          remove isinf() workaround for VMS

There are compilers that do not treat well POSIX functions - like
getline - usage in the structs.

Older VMS compilers could digest this... but the newer OpenVMS compilers
( like VSI C x86-64 X7.4-843 (GEM 50XB9) ) cannot deal with these
structs. This could be limited to getline() that is defined via
getdelim() and might not affect all POSIX functions in general - but
avoiding POSIX function names usage in the structs is a "safe side"
practice without compromising the functionality or the code readability.

The previous OpenVMS X86 port used a workaround limiting the compiler
capabilities using __CRTL_VER_OVERRIDE=80400000
In order to make the OpenVMS port future proof, this pull request
proposes a possible solution.

closes: #13704

Signed-off-by: Zoltan Arpadffy <zoltan.arpadffy@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/eval.c b/src/eval.c
index 877a20f..6f88e03 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -133,9 +133,9 @@
 	return;
 
     evalarg->eval_cstack = eap->cstack;
-    if (sourcing_a_script(eap) || eap->getline == get_list_line)
+    if (sourcing_a_script(eap) || eap->ea_getline == get_list_line)
     {
-	evalarg->eval_getline = eap->getline;
+	evalarg->eval_getline = eap->ea_getline;
 	evalarg->eval_cookie = eap->cookie;
     }
 }
@@ -7542,7 +7542,7 @@
 	    sticky_cmdmod_flags = cmdmod.cmod_flags
 						& (CMOD_LEGACY | CMOD_VIM9CMD);
 	    do_cmdline((char_u *)ga.ga_data,
-		       eap->getline, eap->cookie, DOCMD_NOWAIT|DOCMD_VERBOSE);
+		       eap->ea_getline, eap->cookie, DOCMD_NOWAIT|DOCMD_VERBOSE);
 	    sticky_cmdmod_flags = save_sticky_cmdmod_flags;
 	}
     }