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/vim9class.c b/src/vim9class.c
index a1f4aa2..ec1bb86 100644
--- a/src/vim9class.c
+++ b/src/vim9class.c
@@ -1369,7 +1369,7 @@
 
     if (!current_script_is_vim9()
 		|| (cmdmod.cmod_flags & CMOD_LEGACY)
-		|| !getline_equal(eap->getline, eap->cookie, getsourceline))
+		|| !getline_equal(eap->ea_getline, eap->cookie, getsourceline))
     {
 	if (is_class)
 	    emsg(_(e_class_can_only_be_defined_in_vim9_script));
@@ -1530,7 +1530,7 @@
     for (;;)
     {
 	vim_free(theline);
-	theline = eap->getline(':', eap->cookie, 0, GETLINE_CONCAT_ALL);
+	theline = eap->ea_getline(':', eap->cookie, 0, GETLINE_CONCAT_ALL);
 	if (theline == NULL)
 	    break;
 	char_u *line = skipwhite(theline);
@@ -1778,7 +1778,7 @@
 	    ea.cmd = line;
 	    ea.arg = p;
 	    ea.cmdidx = CMD_def;
-	    ea.getline = eap->getline;
+	    ea.ea_getline = eap->ea_getline;
 	    ea.cookie = eap->cookie;
 
 	    ga_init2(&lines_to_free, sizeof(char_u *), 50);
@@ -2177,7 +2177,7 @@
 
     if (!current_script_is_vim9()
 		|| (cmdmod.cmod_flags & CMOD_LEGACY)
-		|| !getline_equal(eap->getline, eap->cookie, getsourceline))
+		|| !getline_equal(eap->ea_getline, eap->cookie, getsourceline))
     {
 	emsg(_(e_type_can_only_be_defined_in_vim9_script));
 	return;