YACC Make Rule Fails when building from source with nmake
Check out Ruby from svn. Build it using VC2008 and nmake.
nmake will try to compile .y files to .c files. Assuming that you have bison and sed installed (via cygwin or msys) this fails because nmake grabs the y.c rule from the common.mk file, which is designed for GNU make.
$(YACC) -d $(YFLAGS) -o y.tab.c $(<:\=/)
It should be:
$(YACC) -d $(YFLAGS) -o y.tab.c $(<:=/)
The attached patch adds the correct rule to Makefile.sub for nmake, leaving the GNUMake one alone.