libtool: Fix support for NIOS2 processor

The name of the system contains the string "nios2". This string
is caught by the some of the greedy checks for OS/2 in libtool,
in particular the *os2* branches of switch statements match for
the nios2 string, which results in incorrect behavior of libtool.

Switch to use $host_os instead of $host and tweak the patterns to
match to avoid this problem for nios2.

* build-aux/ltmain.in: Fix NIOS2 support
---
 build-aux/ltmain.in | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

Submitted: https://lists.gnu.org/archive/html/libtool-patches/2021-10/msg00021.html
Reworked and submitted: https://lists.gnu.org/archive/html/libtool-patches/2024-01/msg00068.html
Upstream-Status: Backport [https://git.savannah.gnu.org/cgit/libtool.git/commit/?id=49e6cb0d4dfdca2a59b909dc4532fe22dbc57ad5]

Index: libtool-2.4.7/build-aux/ltmain.in
===================================================================
--- libtool-2.4.7.orig/build-aux/ltmain.in
+++ libtool-2.4.7/build-aux/ltmain.in
@@ -518,10 +518,10 @@ libtool_validate_options ()
     # preserve --debug
     test : = "$debug_cmd" || func_append preserve_args " --debug"
 
-    case $host in
+    case $host_os in
       # Solaris2 added to fix http://debbugs.gnu.org/cgi/bugreport.cgi?bug=16452
       # see also: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59788
-      *cygwin* | *mingw* | *pw32* | *cegcc* | *solaris2* | *os2*)
+      cygwin* | mingw* | pw32* | cegcc* | solaris2* | os2*)
         # don't eliminate duplications in $postdeps and $predeps
         opt_duplicate_compiler_generated_deps=:
         ;;
@@ -6273,8 +6273,8 @@ func_mode_link ()
 	fi
 	if test -n "$library_names" &&
 	   { test no = "$use_static_libs" || test -z "$old_library"; }; then
-	  case $host in
-	  *cygwin* | *mingw* | *cegcc* | *os2*)
+	  case $host_os in
+	  cygwin* | mingw* | cegcc* | os2*)
 	      # No point in relinking DLLs because paths are not encoded
 	      func_append notinst_deplibs " $lib"
 	      need_relink=no
@@ -6343,8 +6343,8 @@ func_mode_link ()
 	      soname=$dlname
 	    elif test -n "$soname_spec"; then
 	      # bleh windows
-	      case $host in
-	      *cygwin* | mingw* | *cegcc* | *os2*)
+	      case $host_os in
+	      cygwin* | mingw* | cegcc* | os2*)
 	        func_arith $current - $age
 		major=$func_arith_result
 		versuffix=-$major