libtool: use false or : for $preload, and simplify

* build-aux/ltmain.m4sh (func_mode_link): Save a string
comparison by setting $preload to false or : and using it directly
instead of if statements.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>

build-aux/ltmain.m4sh

@@ -4388,7 +4388,7 @@ func_mode_link ()
     non_pic_objects=
     precious_files_regex=
     prefer_static_libs=no
-    preload=no
+    preload=false
     prev=
     prevarg=
     release=
@@ -4471,12 +4471,12 @@ func_mode_link ()
 	  continue
 	  ;;
 	dlfiles|dlprefiles)
-	  if test no = "$preload"; then
+	  $preload || {
 	    # Add the symbol object into the linking commands.
 	    func_append compile_command " @SYMFILE@"
 	    func_append finalize_command " @SYMFILE@"
-	    preload=yes
-	  fi
+	    preload=:
+	  }
 	  case $arg in
 	  *.la | *.lo) ;;  # We handle these cases below.
 	  force)
@@ -7949,7 +7949,7 @@ EOF
       test -n "$release" && \
 	func_warning "\`-release' is ignored for programs"
 
-      test yes = "$preload" \
+      $preload \
 	&& test unknown = "$dlopen_support" \
 	&& test unknown = "$dlopen_self" \
 	&& test unknown = "$dlopen_self_static" \
@@ -8344,9 +8344,8 @@ EOF
 	  build_libtool_libs=no
 	else
 	  oldobjs="$old_deplibs $non_pic_objects"
-	  if test yes = "$preload" && test -f "$symfileobj"; then
-	    func_append oldobjs " $symfileobj"
-	  fi
+	  $preload && test -f "$symfileobj" \
+	    && func_append oldobjs " $symfileobj"
 	fi
 	addlibs=$old_convenience
       fi