Make MinGW compile using a remote build directory.

This patch fixes a few MinGW specific issues that prevented it
from building in a remote directory.

Makefile.in

@@ -79,8 +79,8 @@ all: dep config.h _pli_types.h version_tag.h ivl@EXEEXT@ version.exe
 # dosify text files.
 ifeq (@MINGW32@,yes)
 all: dep dosify.exe
-dosify.exe: dosify.c
-	$(CC) -o dosify.exe dosify.c
+dosify.exe: $(srcdir)/dosify.c
+	$(CC) -o dosify.exe $(srcdir)/dosify.c
 endif
 
 # This rule rules the compiler in the trivial hello.vl program to make

driver-vpi/Makefile.in

@@ -56,14 +56,14 @@ distclean: clean
 	rm -f Makefile config.log
 
 Makefile: $(srcdir)/Makefile.in ../config.status
-	../config.status --file=$@
+	cd ..; ./config.status --file=driver-vpi/$@
 
 O = main.o res.o
 
 iverilog-vpi@EXEEXT@: $O
 	$(CC) $(LDFLAGS) $O -o iverilog-vpi@EXEEXT@ @EXTRALIBS@
 
-main.o: main.c config.h
+main.o: $(srcdir)/main.c config.h
 	$(CC) $(CPPFLAGS) $(CFLAGS) -c $(srcdir)/main.c