Use GNU strip for compare-debug on Solaris.

Solaris strip intentionally preserves symbol tables in relocatable objects.
That keeps the objects linkable, but it means GCC's compare-debug helper can
report differences after debug stripping even when GNU strip produces matching
objects.  Prefer gstrip on SunOS for this diagnostic comparison.

--- gcc-16.1.0/contrib/compare-debug
+++ gcc-16.1.0/contrib/compare-debug
@@ -57,6 +57,21 @@
 
 trap 'rm -f "$1.$suf1" "$2.$suf2"' 0 1 2 15
 
+strip_cmd=${STRIP:-strip}
+case `uname -s` in
+SunOS)
+  # Solaris strip preserves symbol tables in relocatable objects; use GNU strip
+  # for this comparison so object-code identity is not hidden by debug data.
+  if test "${STRIP+set}" != set; then
+    if command -v gstrip > /dev/null 2>&1; then
+      strip_cmd=gstrip
+    elif test -x /usr/gnu/bin/gstrip; then
+      strip_cmd=/usr/gnu/bin/gstrip
+    fi
+  fi
+  ;;
+esac
+
 case `uname -s` in
 Darwin)
   # The strip command on darwin does not remove all debug info.
@@ -66,10 +81,10 @@
   ;;
 *)
   cp "$1" "$1.$suf1"
-  strip "$1.$suf1"
+  $strip_cmd "$1.$suf1"
 
   cp "$2" "$2.$suf2"
-  strip "$2.$suf2"
+  $strip_cmd "$2.$suf2"
   ;;
 esac
 
@@ -157,13 +172,13 @@
 
       objcopy $rsopts "$2.$suf2" "$2.$suf4"
       mv "$2.$suf4" "$2.$suf2"
-    elif (strip --help) 2>&1 | grep ' --remove-section' > /dev/null; then
+    elif ($strip_cmd --help) 2>&1 | grep ' --remove-section' > /dev/null; then
       cp "$1.$suf1" "$1.$suf3"
-      strip $rsopts "$1.$suf3"
+      $strip_cmd $rsopts "$1.$suf3"
       mv "$1.$suf3" "$1.$suf1"
 
       cp "$2.$suf2" "$2.$suf4"
-      strip $rsopts "$2.$suf4"
+      $strip_cmd $rsopts "$2.$suf4"
       mv "$2.$suf4" "$2.$suf2"
     else
       echo failed to strip off .eh_frame >&2