Re-enable nmake runirb

Skip RUBY_ON_BUG gdb hook on MSVC (MSC_VER) builds

Author: YO4

common.mk

@@ -1421,11 +1421,14 @@ $(srcdir)/ext/etc/constdefs.h: $(srcdir)/ext/etc/depend
 run: yes-fake miniruby$(EXEEXT) PHONY
 	$(BTESTRUBY) $(RUNOPT0) $(TESTRUN_SCRIPT) $(RUNOPT)
 
+# Don't use RUBY_ON_BUG if MSC_VER is present
+RUBY_ON_BUG_SPEC$(MSC_VER) = RUBY_ON_BUG='gdb -x $(srcdir)/.gdbinit -p'
+
 runruby: $(PROGRAM) PHONY
-	RUBY_ON_BUG='gdb -x $(srcdir)/.gdbinit -p' $(RUNRUBY) $(RUNOPT0) $(TESTRUN_SCRIPT) $(RUNOPT)
+	$(RUBY_ON_BUG_SPEC) $(RUNRUBY) $(RUNOPT0) $(TESTRUN_SCRIPT) $(RUNOPT)
 
 runirb: $(PROGRAM) update-default-gemspecs
-	RUBY_ON_BUG='gdb -x $(srcdir)/.gdbinit -p' $(RUNRUBY) $(RUNOPT0) -rrubygems -r irb -e 'IRB.start("make runirb")' $(RUNOPT)
+	$(RUBY_ON_BUG_SPEC) $(RUNRUBY) $(RUNOPT0) -rrubygems -r irb -e 'IRB.start("make runirb")' $(RUNOPT)
 
 parse: yes-fake miniruby$(EXEEXT) PHONY
 	$(BTESTRUBY) --dump=parsetree_with_comment,insns $(TESTRUN_SCRIPT)