remove LNK4217 warning spam from Windows build

it just makes the build error logs harder to read.
it's not like we are ever going to fix it.

Change-Id: I26be4deb7b72d142fcee62ea3eee2dd0bd607716
Reviewed-on: https://gerrit.libreoffice.org/20284Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>

solenv/gbuild/platform/windows.mk

@@ -50,4 +50,9 @@ gb_Executable_LAYER := \
 # empty to avoid --warn-undefined-functions
 gb_Library__set_soversion_script_platform =
 
+# Prevent warning spamming
+# Happens because of the way we link our unit tests with our libraries.
+gb_LinkTarget_LDFLAGS += \
+	/ignore:4217
+
 # vim:set noexpandtab: