YaHTTP needs Boost headers, and those are in /usr/local/include on FreeBSD.
Append BOOST_CPPFLAGS to AM_CPPFLAGS in configure.ac, so every Makefile uses them.
Also set the compiler flags globally, so that we compile yahttp with the same settings.
Fixes "/reqresp.hpp:7:10: fatal error: 'boost/function.hpp' file not found"
-AM_CPPFLAGS = $(LUA_CFLAGS) $(LIBEDIT_CFLAGS) $(YAHTTP_CFLAGS) $(BOOST_CPPFLAGS) $(SANITIZER_FLAGS) -O3 -Wall -pthread -DSYSCONFDIR=\"${sysconfdir}\"
+AM_CPPFLAGS += $(LUA_CFLAGS) $(LIBEDIT_CFLAGS) $(YAHTTP_CFLAGS) $(SANITIZER_FLAGS) -DSYSCONFDIR=\"${sysconfdir}\"
ACLOCAL_AMFLAGS = -I m4
])
AC_SUBST([PROGRAM_LDFLAGS])
+AC_SUBST([AM_CPPFLAGS],
+ ["AS_ESCAPE([-I$(top_builddir) -I$(top_srcdir)]) -Wall -O3 -pthread $BOOST_CPPFLAGS"]
+)
+
AC_CONFIG_FILES([Makefile
ext/yahttp/Makefile
ext/yahttp/yahttp/Makefile])