[gcc(refs/users/aoliva/heads/testme)] Introduce x86_64-linux-gnum32

[Alexandre Oliva]

https://gcc.gnu.org/g:cb8e17299c55cac0818b13c4dd612a35f622fd14

commit cb8e17299c55cac0818b13c4dd612a35f622fd14
Author: Olivier Hainque <hainque@adacore.com>
Date:   Mon Oct 27 20:16:56 2025 -0300

    Introduce x86_64-linux-gnum32
    
    Enable a 32-bit "native" toolchain to be built on x86_64-linux-gnu,
    i.e., one that targets -m32 despite running in 64-bit mode.  Neither
    multilibs nor -m64 support are desired for this configuration (a
    multilibbed x86_64-linux-gnu native, defaulting to -m32 through self
    specs would accomplish those).
    
    for  gcc/ChangeLog
    
            * config.gcc [x86_64-*-*]: Match *m32 target, default to m32
            abi and multilib.  Accept 32 or m32 for --with-abi.

Diff:
---
 gcc/config.gcc | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/gcc/config.gcc b/gcc/config.gcc
index d2770ea556b2..952499b494c1 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -676,6 +676,29 @@ i[34567]86-*-*)
 x86_64-*-darwin*)
 	;;
 x86_64-*-*)
+        # Pick a default with_abi and with_multilib_list for m32
+        # restricted toolchains
+        case ${target} in
+        *m32)
+		case ${with_abi} in
+		"" | 32 | m32)
+			with_abi=m32
+			;;
+		*)
+			echo "Invalid --with-abi=$with_abi for m32 target"
+			exit 1
+	       esac
+	       case ${with_multilib_list} in
+	       default | m32)
+			with_multilib_list=m32
+			;;
+	       *)
+			echo "Invalid multilib list for m32 target"
+			exit 1
+	       esac
+	       ;;
+	esac
+
 	case ${with_abi} in
 	"")
 		if test "x$with_multilib_list" = xmx32; then
@@ -690,6 +713,8 @@ x86_64-*-*)
 	x32 | mx32)
 		tm_file="i386/biarchx32.h ${tm_file}"
 		;;
+	32 | m32)
+		;;
 	*)
 		echo "Unknown ABI used in --with-abi=$with_abi"
 		exit 1