fix perl module build on openbsd

unfortunately, some mangling is needed to create the correct linker
and compiler invocations

meson.build

@@ -406,6 +406,12 @@ if want_capsicum
   endif
 endif
 
+# dependency helper sets
+dep_cflagsonly = []
+foreach d : dep
+  dep_cflagsonly += d.partial_dependency(includes : true, compile_args : true)
+endforeach
+
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 # irssi-config.h #
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