设置路径！

export PATH=$PATH:/home/XXX/toolchain4/pre/bin

make sure the cross compiler tool chain can be found in the $PATH 这样才可以查找到arm-apple-darwin9-gcc等

PjSIP Compilation

Getting pjsip source code

1. Get PjSIP from subversion repository:

svn checkout http://svn.pjsip.org/repos/pjproject/trunk pjproject

2. Set your config_site.h  (pjlib/include/pj/config_site.h) to the following: 
#define PJ_CONFIG_IPHONE 1
#include <pj/config_site_sample.h>

This will activate iPhone specific settings in the config_site_sample.h.
Media device for ipod/iphone
pjMedia
Download 

iphonesound.c, and save in pjmedia/src/pjmedia directory. 
Complete config.h file in pjmedia/include/pjmedia at line 59 with: 
/** Constant for AudioQueue sound backend. */
#define PJMEDIA_SOUND_IPHONE_SOUND          3
Configuration
Complete aconfigure.ac file at line 572with:(并删除掉自带的，比较区别)
  arm-apple-darwin*)
        LIBS="$LIBS -framework CoreAudio -framework CoreFoundation -framework AudioToolbox"
        ac_pjmedia_snd=iphone
        AC_MSG_RESULT([Checking sound device backend... AudioQueue])
        ;;
Complete os-auto.mak.in in pjmedia/build at line 150 with following lines:
#
# iPod/iPhone
#
ifeq ($(AC_PJMEDIA_SND),iphone)
export SOUND_OBJS = iphonesound.o
INCLUDE_IPHONE=/path/of/include/in/iphone/sdk
export CFLAGS += -DPJMEDIA_SOUND_IMPLEMENTATION=PJMEDIA_SOUND_IPHONE_SOUND \
        -D__COREAUDIO_USE_FLAT_INCLUDES__ \
        -I$(INCLUDE_IPHONE)/AudioToolbox \
        -I$(INCLUDE_IPHONE)/CoreAudio \
        -I$(INCLUDE_IPHONE)/CarbonCore \
        -I$(INCLUDE_IPHONE)/CoreFoundation
endif
其中 /path/of/include/in/iphone/sdk

 类似于/home/XXX/toolchain4/sys/usr/include
 
Generate configuration script 
autoconf aconfigure.ac > aconfigure
 
Compilation
1. Configure pjsip without codec except G711 and GSM: 
./aconfigure --host=arm-apple-darwin9 \
  --disable-speex-aec --disable-speex-codec \
  --disable-l16-codec --disable-g722-codec  --disable-ilbc-codec
 
可通过如下指令查看供选的编译选项： The list of customizable features can be viewed by running "./configure --help" command:
 
 Below is an example of specifying CFLAGS in configure:
$ ./configure  CFLAGS="-O3 -DNDEBUG -msoft-float -fno-builtin"

...
./aconfigure CC="clang" CFLAGS="-ccc-host-triple arm-apple-darwin9" --host=arm-apple-darwin9   --disable-speex-aec --disable-speex-codec --disable-l16-codec --disable-g722-codec --disable-ilbc-codec
有如下错误：
checking whether the C compiler works... no

aconfigure: error: in `/home/grant/pjproject':

aconfigure: error: C compiler cannot create executables

See `config.log' for more details

config.log里面显示：aconfigure:2823: clang -ccc-host-triple arm-apple-darwin9   conftest.c  >&5
ld: library not found for -lcrt1.10.5.o
解决办法：
 
正解在这里：http://stackoverflow.com/questions/1365211/error-in-xcode-project-ld-library-not-found-for-lcrt1-10-6-o
照做，Edit Project Settings－>Build，将MACOSX_DEPLOYMENT_TARGET 由Compiler default修改为10.6。OK。

 
 
2. make dep
 “
This was the output when you run  :      
checking for arm-elf-linux-gcc... no      
checking for gcc... gcc     
 checking for C compiler default output file name... a.out     
 checking whether the C compiler works... yes      
checking whether we are cross compiling... no
”

3. make
  1).  类似上篇文章，需要增补绝对路径
  2).  报错：
/toolchain4/sys/usr/include/Foundation/NSString.h:282: error: format string argument follows the args to be formatted
其实是上篇文章toolchain搭建遗留的问题，参考：http://code.google.com/p/iphonedevonlinux/wiki/Installation
解决办法：  原来是sdk4的头文件有问题，对比一下sdk3的，把出问题的语句行的多余部分去掉就可以了。。。。Foundation和UIkit下面的几个头文件也有问题，把出错的语句行的^字符改为*就可以
 ” I did a little reading and the '^' token has to do with Apple's block syntax that they have added to the language:
http://developer.apple.com/mac/articles/cocoa/introblocksgcd.html
These extensions must have been added for iOS 4 and the compiler built by this script doesn't support them. “
 
"format string argument follows the args to be formatted" 

Only clang can compile the new Apple headers containing new 'Blocks' feature. gcc can't.
 
 
【必看参考文献】：
1. http://trac.pjsip.org/repos/wiki/Getting-Started/Autoconf
2.  

http://code.google.com/p/ios-toolchain-based-on-clang-for-linux/wiki/HowTo_en  第二种方法！！！暂未试
 
小技巧：
若make dep 出现如下error： .pjmedia-arm-apple-darwin9.depend:1:***

 missing separator.  Stop.

make[1]:***[pjmedia]Error2
则手动将所提示build目录下的 ..depend 文件统统删除。重试即可。