installer-windows: Add x64 installer build via command line

Add a new variable to know on which platform we are compiling.

Make the msbuild command to be aware of the platform we want to build.

Shorter the msbuild parameters from `property:`->`p:`. Change slashes
to double slashes so msys does not get confused.

Signed-off-by: Alin Gabriel Serdean <aserdean@ovn.org>
Acked-by: Alin Balutoiu <abalutoiu@cloudbasesolutions.com>

Makefile.am

@@ -20,6 +20,7 @@ AM_CPPFLAGS += $(PTHREAD_INCLUDES)
 AM_CPPFLAGS += $(MSVC_CFLAGS)
 AM_LDFLAGS += $(PTHREAD_LDFLAGS)
 AM_LDFLAGS += $(MSVC64_LDFLAGS)
+PLATFORM = $(MSVC_PLATFORM)
 endif
 
 AM_CPPFLAGS += -I $(top_srcdir)/include

m4/openvswitch.m4

@@ -79,11 +79,14 @@ AC_DEFUN([OVS_CHECK_WIN64],
      if (cl) 2>&1 | grep 'x64' >/dev/null 2>&1; then
        cl_cv_x64=yes
        MSVC64_LDFLAGS=" /MACHINE:X64 "
+       MSVC_PLATFORM="x64"
      else
        cl_cv_x64=no
        MSVC64_LDFLAGS=""
+       MSVC_PLATFORM="x86"
      fi])
      AC_SUBST([MSVC64_LDFLAGS])
+     AC_SUBST([MSVC_PLATFORM])
 ])
 
 dnl Checks for WINDOWS.

windows/automake.mk

@@ -35,7 +35,7 @@ windows_installer: all
 	cp -f $(top_srcdir)/datapath-windows/x64/Win8.1$(VSTUDIO_CONFIG)/package/ovsext.cat windows/ovs-windows-installer/Driver/Win8.1/ovsext.cat
 	cp -f $(top_srcdir)/datapath-windows/x64/Win8.1$(VSTUDIO_CONFIG)/package/ovsext.inf windows/ovs-windows-installer/Driver/Win8.1/ovsext.inf
 	cp -f $(top_srcdir)/datapath-windows/x64/Win8.1$(VSTUDIO_CONFIG)/package/ovsext.sys windows/ovs-windows-installer/Driver/Win8.1/ovsext.sys
-	MSBuild.exe windows/ovs-windows-installer.sln //nologo /target:Build /property:Configuration="Release" /property:Version="$(PACKAGE_VERSION)"
+	MSBuild.exe windows/ovs-windows-installer.sln //nologo //target:Build //p:Configuration="Release" //p:Version="$(PACKAGE_VERSION)" //p:Platform=$(PLATFORM)
 
 EXTRA_DIST += \
 	windows/automake.mk \