Try to fix error on Solaris

https://rubyci.s3.amazonaws.com/solaris10-sunc/ruby-master/log/20220428T000004Z.fail.html.gz
```
linking static-library libruby-static.a
/bin/sh: syntax error at line 8: `(' unexpected
gmake: *** [Makefile:318: libruby-static.a] Error 2
exit 2
failed(make)
```

template/Makefile.in

@@ -319,7 +319,7 @@ $(LIBRUBY_A):
 		  $(MAKEDIRS) '$(CARGO_TARGET_DIR)/libyjit/' && \
 		  $(CP) '$(YJIT_LIBS)' '$(CARGO_TARGET_DIR)/libyjit/' && \
 		  (cd '$(CARGO_TARGET_DIR)/libyjit/' && $(AR) -x libyjit.a) && \
-		  $(AR) $(ARFLAGS) $@ $$(find '$(CARGO_TARGET_DIR)/libyjit/' -name '*.o') ;
+		  $(AR) $(ARFLAGS) $@ `find '$(CARGO_TARGET_DIR)/libyjit/' -name '*.o'` ;
 		@-$(RANLIB) $@ 2> /dev/null || true
 
 verify-static-library: $(LIBRUBY_A)