patch 8.2.4928: various white space and cosmetic mistakes

Problem:    Various white space and cosmetic mistakes.
Solution:   Change spaces to tabs, improve comments.
diff --git a/src/os_unix.c b/src/os_unix.c
index a51f034..b786f8d 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -1778,10 +1778,10 @@
 {
     if (eap->arg != NULL && STRLEN(eap->arg) > 0)
     {
-        if (xterm_display_allocated)
-            vim_free(xterm_display);
-        xterm_display = (char *)vim_strsave(eap->arg);
-        xterm_display_allocated = TRUE;
+	if (xterm_display_allocated)
+	    vim_free(xterm_display);
+	xterm_display = (char *)vim_strsave(eap->arg);
+	xterm_display_allocated = TRUE;
     }
     smsg(_("restoring display %s"), xterm_display == NULL
 		    ? (char *)mch_getenv((char_u *)"DISPLAY") : xterm_display);
@@ -7210,7 +7210,7 @@
     {
 	if (p_verbose > 0)
 	    smsg_attr(HL_ATTR(HLF_W),
-		        _("Could not load gpm library: %s"), dlerror());
+			       _("Could not load gpm library: %s"), dlerror());
 	return FAIL;
     }