lmdb: fix cross compilation to mingwW64

pkgs/development/libraries/lmdb/bin-ext.patch

···
+diff --git a/libraries/liblmdb/Makefile b/libraries/liblmdb/Makefile
+index 612484e..2e6b562 100644
+--- a/libraries/liblmdb/Makefile
++++ b/libraries/liblmdb/Makefile
+@@ -27,6 +27,7 @@ CFLAGS	= $(THREADS) $(OPT) $(W) $(XCFLAGS)
+ LDLIBS	=
+ SOLIBS	=
+ SOEXT	= .so
++BINEXT  =
+ prefix	= /usr/local
+ exec_prefix = $(prefix)
+ bindir = $(exec_prefix)/bin
+@@ -49,7 +50,7 @@ install: $(ILIBS) $(IPROGS) $(IHDRS)
+ 	mkdir -p $(DESTDIR)$(libdir)
+ 	mkdir -p $(DESTDIR)$(includedir)
+ 	mkdir -p $(DESTDIR)$(mandir)/man1
+-	for f in $(IPROGS); do cp $$f $(DESTDIR)$(bindir); done
++	for f in $(IPROGS); do cp $$f$(BINEXT) $(DESTDIR)$(bindir); done
+ 	for f in $(ILIBS); do cp $$f $(DESTDIR)$(libdir); done
+ 	for f in $(IHDRS); do cp $$f $(DESTDIR)$(includedir); done
+ 	for f in $(IDOCS); do cp $$f $(DESTDIR)$(mandir)/man1; done

pkgs/development/libraries/lmdb/default.nix

···
-{ lib, stdenv, fetchFromGitLab }:
+{ lib, stdenv, fetchFromGitLab, windows }:
 
 stdenv.mkDerivation rec {
   pname = "lmdb";
···
 
   postUnpack = "sourceRoot=\${sourceRoot}/libraries/liblmdb";
 
-  patches = [ ./hardcoded-compiler.patch ];
+  patches = [ ./hardcoded-compiler.patch ./bin-ext.patch ];
   patchFlags = [ "-p3" ];
 
   outputs = [ "bin" "out" "dev" ];
+
+  buildInputs = lib.optional stdenv.hostPlatform.isWindows windows.pthreads;
 
   makeFlags = [
     "prefix=$(out)"
     "CC=${stdenv.cc.targetPrefix}cc"
     "AR=${stdenv.cc.targetPrefix}ar"
   ]
-    ++ lib.optional stdenv.isDarwin "LDFLAGS=-Wl,-install_name,$(out)/lib/liblmdb.so";
+    ++ lib.optional stdenv.isDarwin "LDFLAGS=-Wl,-install_name,$(out)/lib/liblmdb.so"
+    ++ lib.optionals stdenv.hostPlatform.isWindows [ "SOEXT=.dll" "BINEXT=.exe" ];
 
   doCheck = true;
   checkTarget = "test";