Update Windows build info

CHANGELOG.md

@@ -1,6 +1,10 @@
 # Changelog
 Newest updates are at the top of this file.
 
+## Aug 07 2020 - v5.1.1
+* ibmmq - Fix STS structure (#146)
+* Add flag for Windows build that seems no longer to be automatically set by cgo
+
 ## Jul 23 2020 - v5.1.0
 * Update for MQ 9.2.0
 * mqmetric - Add explicit client configuration options
@@ -9,13 +13,13 @@ Newest updates are at the top of this file.
 ## June 1 2020 - v5.0.0
 * Migration for Go modules (requires new major number) (#138)
 * ibmmq - Add all string mapping functions from cmqstrc (#142)
-* ibmmq - Add AIX platform header  
+* ibmmq - Add AIX platform header
 * mqmetric - Permit selection of which statistics to gather for STATQ (ibm-messaging/mq-metric-samples#34)
 * mqmetric - Do not try to subscribe to application resource statistics (STATAPP) for now
 * mqmetric - Add QFile usage status available from MQ 9.1.5
 
 ## Apr 02 2020 - v4.1.4
-* Update for MQ 9.1.5                                           
+* Update for MQ 9.1.5
 * ibmmq - Add message and header compression for MQCD (#137)
 * ibmmq - Set endianness just once (#140)
 * mqmetric - Add better diagnostics when running out of object handles

README.md

@@ -78,8 +78,8 @@ export CGO_LDFLAGS_ALLOW="-Wl,-rpath.*"
 ### Windows
 
 * Install the Go runtime and compiler. On Windows, the common directory is `c:\Go`
-* Ensure you have a gcc-based compiler, for example from the Cygwin distribution.
-I recommend you use the mingw variation, to ensure compiled code can be used on systems without Cygwin installed.
+* Ensure you have a gcc-based compiler. The variant that now seems to be recommended for cgo is
+the [tdm-gcc-64](https://jmeubank.github.io/tdm-gcc/download/) 64-bit compiler suite.
 The default `gcc` compiler from Cygwin does not work because it tries to build a
 Cygwin-enabled executable but the MQ libraries do not work in that model;
 the `mingw` versions build Windows-native programs.

ibmmq/mqi.go

@@ -43,7 +43,7 @@ package ibmmq
 /*
 #cgo !windows,!aix CFLAGS: -I/opt/mqm/inc -D_REENTRANT
 #cgo  aix          CFLAGS: -I/usr/mqm/inc -D_REENTRANT
-#cgo  windows      CFLAGS:  -I"C:/Program Files/IBM/MQ/Tools/c/include"
+#cgo  windows      CFLAGS:  -I"C:/Program Files/IBM/MQ/Tools/c/include" -D_WIN64
 #cgo !windows,!aix,!darwin LDFLAGS: -L/opt/mqm/lib64 -lmqm_r -Wl,-rpath,/opt/mqm/lib64 -Wl,-rpath,/usr/lib64
 #cgo darwin                LDFLAGS: -L/opt/mqm/lib64 -lmqm_r -Wl,-rpath,/opt/mqm/lib64 -Wl,-rpath,/usr/lib64
 #cgo aix                   LDFLAGS: -L/usr/mqm/lib64 -lmqm_r