--- mpdecimal-2.4.2/configure.ac.orig	2016-02-27 16:55:00.000000000 -0500
+++ mpdecimal-2.4.2/configure.ac	2017-02-14 09:04:56.759794200 -0500
@@ -5,19 +5,51 @@
 AC_CONFIG_FILES([Makefile libmpdec/Makefile tests/Makefile libmpdec/mpdecimal.h])
 AC_ARG_VAR(MACHINE, [force configuration: x64, uint128, ansi64, ppro, ansi32, ansi-legacy])
 
-LIBSTATIC=libmpdec.a
-LIBSONAME=libmpdec.so.2
-LIBSHARED=libmpdec.so.2.4.2
-AC_SUBST(LIBSTATIC)
-AC_SUBST(LIBSONAME)
-AC_SUBST(LIBSHARED)
-
-
-# Apparently purely informational for this particular build:
 AC_CANONICAL_HOST
 AC_SUBST(build)
 AC_SUBST(host)
 
+case $host in
+  *-*-mingw*)
+  LIBSTATIC=libmpdec.a
+  LIBSOALIAS=
+  LIBSONAME=libmpdec-${PACKAGE_VERSION}.dll
+  LIBSHARED=libmpdec-2.dll
+  LIBIMPORT=libmpdec.dll.a
+  IS_WINDOWS=yes
+  ;;
+  *-*-cygwin*)
+  LIBSTATIC=libmpdec.a
+  LIBSOALIAS=
+  LIBSONAME=cygmpdec-2.dll
+  LIBSHARED=cygmpdec-${PACKAGE_VERSION}.dll
+  LIBIMPORT=libmpdec.dll.a
+  IS_WINDOWS=yes
+  ;;
+  *-*-msys*)
+  LIBSTATIC=libmpdec.a
+  LIBSOALIAS=
+  LIBSONAME=msys-mpdec-2.dll
+  LIBSHARED=msys-mpdec-${PACKAGE_VERSION}.dll
+  LIBIMPORT=libmpdec.dll.a
+  IS_WINDOWS=yes
+  ;;
+  *)
+  LIBSTATIC=libmpdec.a
+  LIBSOALIAS=libmpdec.so
+  LIBSONAME=libmpdec.so.2
+  LIBSHARED=libmpdec.so.2.4.2
+  LIBIMPORT=
+  IS_WINDOWS=no
+  ;;
+esac
+AC_SUBST(LIBSTATIC)
+AC_SUBST(LIBSOALIAS)
+AC_SUBST(LIBSONAME)
+AC_SUBST(LIBSHARED)
+AC_SUBST(LIBIMPORT)
+AC_SUBST(IS_WINDOWS)
+
 # Language and compiler:
 AC_LANG_C
 saved_cflags=$CFLAGS
@@ -88,6 +120,10 @@
 AC_PROG_INSTALL
 AC_SUBST(INSTALL)
 
+# ln -s program
+AC_PROG_LN_S
+AC_SUBST(LN_S)
+
 # _FORTIFY_SOURCE wrappers for memmove and bcopy are incorrect:
 # http://sourceware.org/ml/libc-alpha/2010-12/msg00009.html
 AC_MSG_CHECKING(for glibc _FORTIFY_SOURCE/memmove bug)
--- mpdecimal-2.4.2/libmpdec/Makefile.in.orig	2016-02-27 16:55:00.000000000 -0500
+++ mpdecimal-2.4.2/libmpdec/Makefile.in	2017-02-14 09:58:38.908029100 -0500
@@ -7,6 +7,13 @@
 LIBSTATIC = @LIBSTATIC@
 LIBSONAME = @LIBSONAME@
 LIBSHARED = @LIBSHARED@
+#In Unix-like systems, used to denote a so without a version number
+LIBSOALIAS= @LIBSOALIAS@
+#LIBIMPORT may be empty.  It's only for systems where you link
+# to a separate import file, rather than directly to the shared
+# file.  
+LIBIMPORT = @LIBIMPORT@
+IS_WINDOWS= @IS_WINDOWS@
 
 CC = @CC@
 LD = @LD@
@@ -17,6 +24,8 @@
 MPD_PREC = @MPD_PREC@
 MPD_DPREC = @MPD_DPREC@
 
+LN_S      = @LN_S@
+
 CONFIGURE_CFLAGS = @CONFIGURE_CFLAGS@
 MPD_CFLAGS = $(strip $(CONFIGURE_CFLAGS) $(CFLAGS))
 
@@ -37,7 +46,11 @@
 ifeq ($(shell uname), Darwin)
   MPD_SOFLAGS=-dynamiclib -Wl,-install_name,$(LIBSONAME)
 else
-  MPD_SOFLAGS=-shared -Wl,-soname,$(LIBSONAME)
+  ifneq ($(LIBIMPORT),)
+    MPD_SOFLAGS=-shared -Wl,-soname,$(LIBSONAME),--out-implib,$(LIBIMPORT)
+  else
+    MPD_SOFLAGS=-shared -Wl,-soname,$(LIBSONAME)
+  endif
 endif
 
 
@@ -60,8 +73,10 @@
 
 $(LIBSHARED): Makefile $(SHARED_OBJS)
 	$(LD) $(MPD_LDFLAGS) $(MPD_SOFLAGS) -o $(LIBSHARED) $(SHARED_OBJS) -lm
-	ln -sf $(LIBSHARED) libmpdec.so
-	ln -sf $(LIBSHARED) $(LIBSONAME)
+ifneq ($(LIBSOALIAS),)
+	$(LN_S) $(LIBSHARED) $(LIBSOALIAS)
+endif
+	$(LN_S) $(LIBSHARED) $(LIBSONAME)
 
 
 basearith.o:\
@@ -220,7 +235,7 @@
 	LD_LIBRARY_PATH=. ./bench_shared $(MPD_PREC) 1000
 	LD_LIBRARY_PATH=. ./bench_shared $(MPD_DPREC) 1000
 	rm -f *.o *.gch .objs/*.o .objs/*.gch bench bench_shared
-	rm -f $(LIBSTATIC) $(LIBSHARED) $(LIBSONAME) libmpdec.so
+	rm -f $(LIBSTATIC) $(LIBSHARED) $(LIBSONAME) $(LIBSOALIAS)
 
 profile_use: bench bench_shared
 	./bench $(MPD_PREC) 1000
@@ -234,8 +249,12 @@
 
 clean: FORCE
 	rm -f *.o *.so *.gch *.gcda *.gcno *.gcov *.dyn *.dpi *.lock
-	rm -f bench bench_shared $(LIBSTATIC) $(LIBSHARED) $(LIBSONAME) libmpdec.so
+	rm -f bench bench_shared $(LIBSTATIC) $(LIBSHARED) $(LIBSONAME) $(LIBSOALIAS)
 	cd .objs && rm -f *.o *.so *.gch *.gcda *.gcno *.gcov *.dyn *.dpi *.lock
+ifeq ($(IS_WINDOWS),yes)
+	rm -f *.dll *.exe
+	cd .objs && rm -rf *.dll *.exe
+endif
 
 distclean: clean
 	rm -f config.h config.log config.status Makefile mpdecimal.h
--- mpdecimal-2.4.2/Makefile.in.orig	2016-02-27 16:55:00.000000000 -0500
+++ mpdecimal-2.4.2/Makefile.in	2017-02-14 09:58:38.913529400 -0500
@@ -8,12 +8,23 @@
 LIBSTATIC = @LIBSTATIC@
 LIBSONAME = @LIBSONAME@
 LIBSHARED = @LIBSHARED@
+#In Unix-like systems, used to denote a so without a version number
+LIBSOALIAS= @LIBSOALIAS@
+#LIBIMPORT may be empty.  It's only for systems where you link
+# to a separate import file, rather than directly to the shared
+# file.  
+LIBIMPORT = @LIBIMPORT@
 INSTALL = @INSTALL@
+LN_S    = @LN_S@
+EXEEXT  = @EXEEXT@
+# Windows demands some special build rules.
+IS_WINDOWS = @IS_WINDOWS@
 
 prefix = @prefix@
 exec_prefix = @exec_prefix@
 includedir = @includedir@
 libdir = @libdir@
+bindir = @bindir@
 datarootdir = @datarootdir@
 docdir = @docdir@
 
@@ -35,9 +46,23 @@
 	$(INSTALL) -d -m 755 $(DESTDIR)$(includedir)
 	$(INSTALL) -m 644 libmpdec/mpdecimal.h $(DESTDIR)$(includedir)
 	$(INSTALL) -d -m 755 $(DESTDIR)$(libdir)
+ifneq ($(LIBIMPORT),)
+	$(INSTALL) -m 644 libmpdec/$(LIBIMPORT) $(DESTDIR)$(libdir)
+endif
 	$(INSTALL) -m 644 libmpdec/$(LIBSTATIC) $(DESTDIR)$(libdir)
+ifeq ($(IS_WINDOWS),yes)
+	$(INSTALL) -d -m 755 $(DESTDIR)$(bindir)
+	$(INSTALL) -m 755 libmpdec/$(LIBSHARED) $(DESTDIR)$(bindir)
+ifneq ($(LIBSOALIAS),)
+	cd $(DESTDIR)$(bindir) && $(LN_S) $(LIBSHARED) $(LIBSOALIAS)
+endif
+else
 	$(INSTALL) -m 755 libmpdec/$(LIBSHARED) $(DESTDIR)$(libdir)
-	cd $(DESTDIR)$(libdir) && ln -sf $(LIBSHARED) $(LIBSONAME) && ln -sf $(LIBSHARED) libmpdec.so
+	cd $(DESTDIR)$(libdir) && $(LN_S) $(LIBSHARED) $(LIBSONAME)
+ifneq ($(LIBSOALIAS),)
+	cd $(DESTDIR)$(libdir) && $(LN_S) $(LIBSHARED) $(LIBSOALIAS)
+endif
+endif
 	$(INSTALL) -d -m 755 $(DESTDIR)$(docdir)
 	cp -R doc/* $(DESTDIR)$(docdir)
 
--- mpdecimal-2.4.2/tests/Makefile.in.orig	2016-02-27 16:55:00.000000000 -0500
+++ mpdecimal-2.4.2/tests/Makefile.in	2017-02-14 09:58:38.919030700 -0500
@@ -11,6 +11,9 @@
 MPD_WARN = @MPD_WARN@
 MPD_CONFIG = @MPD_CONFIG@
 
+# Windows demands some special build rules.
+IS_WINDOWS = @IS_WINDOWS@
+
 CONFIGURE_CFLAGS = @CONFIGURE_CFLAGS@
 CFLAGS ?= $(CONFIGURE_CFLAGS)
 
@@ -46,6 +49,9 @@
 clean: FORCE
 	rm -f *.o *.gch *.gcda *.gcno *.gcov *.dyn *.dpi *.lock
 	rm -f runtest runtest_shared runtest_alloc runtest_alloc_shared
+ifeq ($(IS_WINDOWS),yes)
+	rm -f *.dll *.exe
+endif
 
 distclean: FORCE
 	$(MAKE) clean
--- mpdecimal-2.4.2/tests/runshort.sh.orig	2016-02-27 16:55:00.000000000 -0500
+++ mpdecimal-2.4.2/tests/runshort.sh	2017-02-14 09:58:38.924030500 -0500
@@ -30,9 +30,21 @@
 
 printf "Running official tests ...\n\n"
 
+case "$(uname -s)" in
+  CYGWIN*|MINGW*|MSYS*)
+  cp ../libmpdec/*.dll .
+  ;;
+esac
+
 if  ! LD_LIBRARY_PATH=../libmpdec ./runtest_shared official.decTest
 then
     printf "\nFAIL\n\n\n"
+    case "$(uname -s)" in
+      CYGWIN*|MINGW*|MSYS*)
+        rm -f *.dll
+      ;;
+    esac
+
     exit 1
 fi
 
@@ -41,8 +53,19 @@
 if ! LD_LIBRARY_PATH=../libmpdec ./runtest_shared additional.decTest
 then
     printf "\nFAIL\n\n\n"
+
+    case "$(uname -s)" in
+      CYGWIN*|MINGW*|MSYS*)
+        rm -f *.dll
+      ;;
+    esac
+
     exit 1
 fi
 
-
+case "$(uname -s)" in
+  CYGWIN*|MINGW*|MSYS*)
+  rm -f *.dll
+  ;;
+esac
 
--- mpdecimal-2.4.2/tests/runshort_alloc.sh.orig	2016-02-27 16:55:00.000000000 -0500
+++ mpdecimal-2.4.2/tests/runshort_alloc.sh	2017-02-14 09:58:38.933031900 -0500
@@ -30,9 +30,21 @@
 
 printf "Running official tests with allocation failures ...\n\n"
 
+case "$(uname -s)" in
+  CYGWIN*|MINGW*|MSYS*)
+  cp ../libmpdec/*.dll .
+  ;;
+esac
+
 if  ! LD_LIBRARY_PATH=../libmpdec ./runtest_alloc_shared official.decTest
 then
     printf "\nFAIL\n\n\n"
+    case "$(uname -s)" in
+      CYGWIN*|MINGW*|MSYS*)
+        rm -f *.dll
+      ;;
+    esac
+
     exit 1
 fi
 
@@ -41,8 +53,18 @@
 if ! LD_LIBRARY_PATH=../libmpdec ./runtest_alloc_shared additional.decTest
 then
     printf "\nFAIL\n\n\n"
+    case "$(uname -s)" in
+      CYGWIN*|MINGW*|MSYS*)
+        rm -f *.dll
+      ;;
+    esac
+
     exit 1
 fi
 
-
+case "$(uname -s)" in
+  CYGWIN*|MINGW*|MSYS*)
+     rm -f *.dll
+  ;;
+esac
 

--- mpdecimal-2.4.2/tests/runtest.c.orig	2017-02-14 18:41:32.763666600 -0500
+++ mpdecimal-2.4.2/tests/runtest.c	2017-02-14 19:38:26.102943000 -0500
@@ -46,6 +46,10 @@
 #include "mptest.h"
 #include "malloc_fail.h"
 
+#if defined(__MINGW32__)
+#define random rand
+#define srandom srand
+#endif
 
 #define MAXLINE 400000
 #define MAXTOKEN 32