因为项目需要在android的NDK开发中使用pcre正则表达式库，而android系统中并没有自带该库，所以就得另外移植了， 下面是移植的详细步骤：

1. 下载pcre源码，可以到http://sourceforge.net/projects/pcre/下载源码。
我这里使用的是pcre-7.8.tar.gz 。

2. 将pcre-7.8 的源码拷贝至android源码树下的external/pcre目录下。

3. 将下面的Android.mk文件拷贝到external/pcre目录下。

Android.mk:

#
#  Android makefile for libpcre
#
#  This makefile generates libpcre.a, pcregrep and pcre.h ONLY.
#  It should be amended to build libpcreposix.a, libpcrecpp.a
#  and tests.


LOCAL_PATH := $(call my-dir)

###
### Build libpcre.a and pcre.h
###

include $(CLEAR_VARS)

#step 1:
# to generate the files  config.h pcre.h pcre_chartables.c 
#
GEN := $(LOCAL_PATH)/config.h
$(GEN): $(LOCAL_PATH)/config.h.generic
    $(hide) cp $(LOCAL_PATH)/config.h.generic $@
LOCAL_GENERATED_SOURCES += $(GEN)

GEN := $(LOCAL_PATH)/pcre.h
$(GEN): $(LOCAL_PATH)/pcre.h.generic
    $(hide) cp $(LOCAL_PATH)/pcre.h.generic $@
LOCAL_GENERATED_SOURCES += $(GEN)

GEN := $(LOCAL_PATH)/pcre_chartables.c
$(GEN): $(LOCAL_PATH)/pcre_chartables.c.dist
    $(hide) cp $(LOCAL_PATH)/pcre_chartables.c.dist $@
LOCAL_GENERATED_SOURCES += $(GEN)

#step 2:
#clear the vars generated by the step 1 
# 
include $(CLEAR_VARS)

LOCAL_SRC_FILES :=  \
  pcre_compile.c \
  pcre_config.c \
  pcre_dfa_exec.c \
  pcre_exec.c \
  pcre_fullinfo.c \
  pcre_get.c \
  pcre_globals.c \
  pcre_info.c \
  pcre_internal.h \
  pcre_maketables.c \
  pcre_newline.c \
  pcre_ord2utf8.c \
  pcre_refcount.c \
  pcre_study.c \
  pcre_tables.c \
  pcre_try_flipped.c \
  pcre_ucd.c \
  pcre_valid_utf8.c \
  pcre_version.c \
  pcre_xclass.c \
  pcre_chartables.c \
  ucp.h \
  pcre.h \
  config.h

#copy the pcre.h to out/target/product/generic/obj/include/libpcre
#
LOCAL_COPY_HEADERS := pcre.h
LOCAL_COPY_HEADERS_TO := libpcre

LOCAL_CFLAGS += -O3 -I. -DHAVE_CONFIG_H

LOCAL_MODULE := libpcre
LOCAL_MODULE_CLASS := STATIC_LIBRARIES
LOCAL_PRELINK_MODULE := false

include $(BUILD_STATIC_LIBRARY)

###
### Build pcregrep
###

include $(CLEAR_VARS)

LOCAL_MODULE := pcregrep
LOCAL_SRC_FILES := pcregrep.c
LOCAL_CFLAGS += -O3 -I. -DHAVE_CONFIG_H
LOCAL_STATIC_LIBRARIES := libpcre

include $(BUILD_EXECUTABLE)

4. cd 到 android的源码树的根目录下，输入命令：

. build/envsetup.sh

chooseproduct
mmm external/pcre
从下面的log可以看到生成了libpcre.a库：

make: Entering directory `/home/braincol/workspace/android/android_build/android_sdk_froyo'
Header: out/target/product/generic/obj/include/libpcre/pcre.h
target thumb C: pcregrep <= external/pcre/pcregrep.c
target thumb C: libpcre <= external/pcre/pcre_compile.c
target thumb C: libpcre <= external/pcre/pcre_config.c
target thumb C: libpcre <= external/pcre/pcre_dfa_exec.c
target thumb C: libpcre <= external/pcre/pcre_exec.c
target thumb C: libpcre <= external/pcre/pcre_fullinfo.c
target thumb C: libpcre <= external/pcre/pcre_get.c
target thumb C: libpcre <= external/pcre/pcre_globals.c
target thumb C: libpcre <= external/pcre/pcre_info.c
target thumb C: libpcre <= external/pcre/pcre_maketables.c
target thumb C: libpcre <= external/pcre/pcre_newline.c
target thumb C: libpcre <= external/pcre/pcre_ord2utf8.c
target thumb C: libpcre <= external/pcre/pcre_refcount.c
target thumb C: libpcre <= external/pcre/pcre_study.c
target thumb C: libpcre <= external/pcre/pcre_tables.c
target thumb C: libpcre <= external/pcre/pcre_try_flipped.c
target thumb C: libpcre <= external/pcre/pcre_ucd.c
target thumb C: libpcre <= external/pcre/pcre_valid_utf8.c
target thumb C: libpcre <= external/pcre/pcre_version.c
target thumb C: libpcre <= external/pcre/pcre_xclass.c
target thumb C: libpcre <= external/pcre/pcre_chartables.c
target StaticLib: libpcre (out/target/product/generic/obj/STATIC_LIBRARIES/libpcre_intermediates/libpcre.a)
target Executable: pcregrep (out/target/product/generic/obj/EXECUTABLES/pcregrep_intermediates/LINKED/pcregrep)
target Non-prelinked: pcregrep (out/target/product/generic/symbols/system/bin/pcregrep)
target Strip: pcregrep (out/target/product/generic/obj/EXECUTABLES/pcregrep_intermediates/pcregrep)
Install: out/target/product/generic/system/bin/pcregrep
make: Leaving directory `/home/braincol/workspace/android/android_build/android_sdk_froyo'

然后只要把libpcre.a库和头文件pcre.h拷贝到你的android应用工程中，然后就可以在ndk中使用这个pcre库了。