Work around missing InetPtonW

...in certain Windows build environments (whatever it is exactly that causes
some Windows builds to fail with "error C3861: 'InetPtonW': identifier not
found" while others succeed).  Unclear what the original reason was for setting
_WIN32_WINNT here, but removing it hopefully does not break anything.

Change-Id: I83222ad010d428cf2b9c447760ea47381552d04a

sal/Library_sal.mk

@@ -213,10 +213,6 @@ else # $(OS) == WNT
 ))
 # .ENDIF
 
-$(eval $(call gb_Library_add_defs,sal,\
-	-D_WIN32_WINNT=0x0502 \
-))
-
 $(eval $(call gb_Library_add_exception_objects,sal,\
 	sal/osl/w32/file \
 	sal/osl/w32/file_dirvol \