Fix generation of PS files and hence PDF files on cygwin.

The Cygwin man command requires that you have a / in the path
if you want to avoid looking at the normal search path. This
patch addes ./ before the manual page file name. Which should
work on any system. It also makes the vvp generation create a
PS file like is done in the other Makefiles.

By default we generate normal manual pages. You can then
create PostScript version and from these you can generate a
PDF version.
(cherry picked from commit 5ae3e48cdb)

Makefile.in

@@ -240,7 +240,7 @@ iverilog-vpi.man: $(srcdir)/iverilog-vpi.man.in version.exe
 	tail -n +2 $(srcdir)/iverilog-vpi.man.in >> $@
 
 iverilog-vpi.ps: iverilog-vpi.man
-	$(MAN) -t iverilog-vpi.man > iverilog-vpi.ps
+	$(MAN) -t ./iverilog-vpi.man > iverilog-vpi.ps
 
 iverilog-vpi.pdf: iverilog-vpi.ps
 	$(PS2PDF) iverilog-vpi.ps iverilog-vpi.pdf

driver/Makefile.in

@@ -89,7 +89,7 @@ iverilog.man: $(srcdir)/iverilog.man.in ../version.exe
 	tail -n +2 $(srcdir)/iverilog.man.in >> $@
 
 iverilog.ps: iverilog.man
-	$(MAN) -t iverilog.man > iverilog.ps
+	$(MAN) -t ./iverilog.man > iverilog.ps
 
 iverilog.pdf: iverilog.ps
 	$(PS2PDF) iverilog.ps iverilog.pdf

vvp/Makefile.in

@@ -59,7 +59,7 @@ all: dep vvp@EXEEXT@ libvpi.a vvp.man
 
 clean:
 	rm -f *.o *~ parse.cc parse.h lexor.cc tables.cc
-	rm -rf dep vvp@EXEEXT@ libvpi.a parse.output vvp.man vvp.pdf vvp.exp
+	rm -rf dep vvp@EXEEXT@ libvpi.a parse.output vvp.man vvp.ps vvp.pdf vvp.exp
 
 distclean: clean
 	rm -f Makefile config.log
@@ -152,8 +152,11 @@ vvp.man: $(srcdir)/vvp.man.in ../version.exe
 	../version.exe `head -1 $(srcdir)/vvp.man.in`'\n' > $@
 	tail -n +2 $(srcdir)/vvp.man.in >> $@
 
-vvp.pdf: vvp.man
-	$(MAN) -t $(srcdir)/vvp.man | $(PS2PDF) - vvp.pdf
+vvp.ps: vvp.man
+	$(MAN) -t ./vvp.man > vvp.ps
+
+vvp.pdf: vvp.ps
+	$(PS2PDF) vvp.ps vvp.pdf
 
 ifeq (@MINGW32@,yes)
 ifeq ($(MAN),none)