Merge #12466: depends: Only use D_DARWIN_C_SOURCE when building miniu…

…pnpc on darwin

992f568 depends: Only use D_DARWIN_C_SOURCE when building miniupnpc on darwin (fanquake)

Pull request description:

  Only use D_DARWIN_C_SOURCE when building on darwin, so we don't inadvertently introduce issues elsewhere.

  cc @theuni

Tree-SHA512: e49a8456ba2b9925c06e62c73e139152b6d63cc5a4cee66944e41c863ca9103e98ac81a5718eceb3d0885a677fc53ece34062b02c304a05c3280e094965e856a

depends/packages/miniupnpc.mk

@@ -6,10 +6,9 @@ $(package)_sha256_hash=90dda8c7563ca6cd4a83e23b3c66dbbea89603a1675bfdb852897c2c9
 
 define $(package)_set_vars
 $(package)_build_opts=CC="$($(package)_cc)"
-$(package)_build_opts_darwin=OS=Darwin LIBTOOL="$($(package)_libtool)"
+$(package)_build_opts_darwin=LIBTOOL="$($(package)_libtool)"
 $(package)_build_opts_mingw32=-f Makefile.mingw
 $(package)_build_env+=CFLAGS="$($(package)_cflags) $($(package)_cppflags)" AR="$($(package)_ar)"
-$(package)_build_env+=CFLAGS=-D_DARWIN_C_SOURCE
 endef
 
 define $(package)_preprocess_cmds