今天研究android的编译系统，在看build/core/pathmap.mk时，有一个地方不理解，下面是文件内容，红色和下划线的说$（１）是模块的列表，我不知道是哪来的，还有怎么是用$(1)表示呢？望哪位大哥指导下。
#
# Copyright (C) 2008 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#
http://www.apache.org/licenses/LICENSE-2.0#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
#
# A central place to define mappings to paths, to avoid hard-coding
# them in Android.mk files.
#
# TODO: Allow each project to define stuff like this before the per-module
# Android.mk files are included, so we don't need to have a big central
# list.
#
#
# A mapping from shorthand names to include directories.
#
pathmap_INCL := \
bluedroid:system/bluetooth/bluedroid/include \
bluez:external/bluetooth/bluez \
glib:external/bluetooth/glib \
bootloader:bootable/bootloader/legacy/include \
corecg:external/skia/include/core \
dbus:external/dbus \
frameworks-base:frameworks/base/include \
graphics:external/skia/include/core \
libc:bionic/libc/include \
libdrm1:frameworks/base/media/libdrm/mobile1/include \
libdrm2:frameworks/base/media/libdrm/mobile2/include \
libhardware:hardware/libhardware/include \
libhardware_legacy:hardware/libhardware_legacy/include \
libhost:build/libs/host/include \
libm:bionic/libm/include \
libnativehelper:dalvik/libnativehelper/include \
libpagemap:system/extras/libpagemap/include \
libril:hardware/ril/include \
libstdc++:bionic/libstdc++/include \
libthread_db:bionic/libthread_db/include \
mkbootimg:system/core/mkbootimg \
recovery:bootable/recovery \
system-core:system/core/include
#
# Returns the path to the requested module's include directory,
# relative to the root of the source tree. Does not handle external
# modules.
#
#
$(1): a list of modules (or other named entities) to find the includes for#
define include-path-for
$(foreach n,$(1),$(patsubst $(n):%,%,$(filter $(n):%,$(pathmap_INCL))))
endef
#
# Many modules expect to be able to say "#include <jni.h>",
# so make it easy for them to find the correct path.
#
JNI_H_INCLUDE := $(call include-path-for,libnativehelper)/nativehelper
#
# A list of all source roots under frameworks/base, which will be
# built into the android.jar.
#
# Note - "common" is included here, even though it is also built
# into a static library (android-common) for unbundled use. This
# is so common and the other framework libraries can have mutual
# interdependencies.
#
FRAMEWORKS_BASE_SUBDIRS := \
$(addsuffix /java, \
core \
graphics \
location \
media \
opengl \
sax \
telephony \
wifi \
vpn \
keystore \
)
#
# A version of FRAMEWORKS_BASE_SUBDIRS that is expanded to full paths from
# the root of the tree. This currently needs to be here so that other libraries
# and apps can find the .aidl files in the framework, though we should really
# figure out a better way to do this.
#
FRAMEWORKS_BASE_JAVA_SRC_DIRS := \
$(addprefix frameworks/base/,$(FRAMEWORKS_BASE_SUBDIRS))
