add module definition file, let vs2019 build correct binary via cmake

Configure for Windows 32 bit:
1. open 'x86 Native Tools Command Prompt for VS 2019', navigate to your source directory
2. configure with cmake:
  cmake -G "Visual Studio 16 2019" -A Win32 -DCMAKE_CONFIGURATION_TYPES=RelWithDebInfo -DCMAKE_INSTALL_PREFIX=/out32/hiredis/ .

Configure for Windows 64 bit:
1. open 'x64 Native Tools Command Prompt for VS 2019', navigate to your source directory
2. configure with cmake:
  cmake -G "Visual Studio 16 2019" -DCMAKE_CONFIGURATION_TYPES=RelWithDebInfo -DCMAKE_INSTALL_PREFIX=/out64/hiredis/ .

Finally, build & install:
  msbuild.exe /p:Configuration=RelWithDebInfo ALL_BUILD.vcxproj
  msbuild.exe /p:Configuration=RelWithDebInfo INSTALL.vcxproj

CMakeLists.txt

@@ -31,7 +31,8 @@ ADD_LIBRARY(hiredis SHARED
     read.c
     sds.c
     sockcompat.c
-    alloc.c)
+    alloc.c
+    hiredis.def)
 
 SET_TARGET_PROPERTIES(hiredis
     PROPERTIES

hiredis.def

@@ -0,0 +1,36 @@
+EXPORTS
+	redisAppendCommand
+	redisAppendCommandArgv
+	redisAppendFormattedCommand
+	redisBufferRead
+	redisBufferWrite
+	redisCommand
+	redisCommand
+	redisCommandArgv
+	redisConnect
+	redisConnectBindNonBlock
+	redisConnectBindNonBlockWithReuse
+	redisConnectFd
+	redisConnectNonBlock
+	redisConnectUnix
+	redisConnectUnixNonBlock
+	redisConnectUnixWithTimeout
+	redisConnectWithOptions
+	redisConnectWithTimeout
+	redisEnableKeepAlive
+	redisFormatCommand
+	redisFormatCommandArgv
+	redisFormatSdsCommandArgv
+	redisFree
+	redisFreeCommand
+	redisFreeKeepFd
+	redisFreeSdsCommand
+	redisGetReply
+	redisGetReplyFromReader
+	redisReaderCreate
+	redisReconnect
+	redisSetTimeout
+	redisvAppendCommand
+	redisvCommand
+	redisvFormatCommand
+	freeReplyObject