$NetBSD$
Look for pcre in PREFIX/include.
Done this way because ocamlc wants a space between -I and the argument,
and the libpcre pkg-config file doesn't have the space.
--- libs/pcre/Makefile.orig 2019-10-25 23:09:16.000000000 +0000
+++ libs/pcre/Makefile
@@ -1,4 +1,4 @@
-ALL_CFLAGS = $(CFLAGS) -I pcre
+ALL_CFLAGS = $(CFLAGS) -I @@PREFIX@@/include
LIBS =
OCAMLOPT=ocamlopt
OCAMLC=ocamlc