kernel: Include openssl headers and dylibs on darwin

The easiest and best way to get openssl on darwin is using homebrew,
however homebrew refuses to link openssl (and for good reason) in
order to prevent conflicts with Apple's homegrown version. Include
the openssl headers and dylibs from the dir that homebrew installs
openssl to let 4.4 kernels compile.

Change-Id: I06b66768fbdd4855fd57b88100d646ed6e311a59

build/tasks/kernel.mk

@@ -262,6 +262,8 @@ endef
 
 ifeq ($(HOST_OS),darwin)
   MAKE_FLAGS += C_INCLUDE_PATH=$(ANDROID_BUILD_TOP)/external/elfutils/libelf/
+  MAKE_FLAGS += C_INCLUDE_PATH=/usr/local/opt/openssl/include
+  MAKE_FLAGS += LIBRARY_PATH=/usr/local/opt/openssl/lib
 endif
 
 ifeq ($(TARGET_KERNEL_MODULES),)