title: unable to compile ffmpeg for iOS
body: <p>I'm trying to compile FFmpeg for iOS (for iPhone5, in order to do some RSTP streaming stuff) following the <a href="http://www.tangentsoftworks.com/blog/2012/11/12/how-to-prepare-your-mac-for-ios-development-with-ffmpeg-libraries/" rel="nofollow">tutorial here</a> but I get stuck with this error : </p>
  
  <pre><code>/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc is unable to create an executable file.
  C compiler test failed.
  </code></pre>
  
  <p>In my config.log file I have this : </p>
  
  <pre><code>BEGIN /var/folders/9g/zv_vdz7x16g1hgx9pqj57zz80000gn/T//ffconf.D3a73otQ.c
          1   int main(void){ return 0; }
  END /var/folders/9g/zv_vdz7x16g1hgx9pqj57zz80000gn/T//ffconf.D3a73otQ.c
  /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc --sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk -arch armv7 -mfpu=neon -miphoneos-version-min=6.0 -mcpu=cortex-a9 -c -o /var/folders/9g/zv_vdz7x16g1hgx9pqj57zz80000gn/T//ffconf.Wv4eZtHX.o /var/folders/9g/zv_vdz7x16g1hgx9pqj57zz80000gn/T//ffconf.D3a73otQ.c
  /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc -arch armv7 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk -miphoneos-version-min=6.0 --sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk -o /var/folders/9g/zv_vdz7x16g1hgx9pqj57zz80000gn/T//ffconf.y84bbrJt /var/folders/9g/zv_vdz7x16g1hgx9pqj57zz80000gn/T//ffconf.Wv4eZtHX.o
  ld: library not found for -lcrt1.3.1.o
  collect2: ld returned 1 exit status
  C compiler test failed.
  </code></pre>
  
  <p>I have other errors with other scripts found on stackoverflow or with google</p>
  
  <p>Any idea ?</p>
  
  <hr>
  
  <p>Ok (i'm kinda new on mac environment), I managed to pass the configure step by fixing the sdk target to the last sdk I have (6.1), removing  Other Linker Flags but then the "make" command is full of errors (either with gcc or arm-apple-darwin10-gcc-4.2) : </p>
  
  <pre><code>In file included from ./libavutil/internal.h:113,
                   from ./libavutil/common.h:385,
                   from ./libavutil/avutil.h:238,
                   from libavdevice/version.h:28,
                   from libavdevice/avdevice.h:22,
                   from libavdevice/alldevices.c:22:
  ./libavutil/libm.h:53: error: static declaration of ‘cbrt’ follows non-static declaration
  ./libavutil/libm.h:60: error: static declaration of ‘cbrtf’ follows non-static declaration
  ./libavutil/libm.h:86: error: expected identifier or ‘(’ before ‘sizeof’
  ./libavutil/libm.h:96: error: expected identifier or ‘(’ before ‘sizeof’
  ./libavutil/libm.h:142: error: static declaration of ‘rint’ follows non-static declaration
  ./libavutil/libm.h:149: error: static declaration of ‘lrint’ follows non-static declaration
  ./libavutil/libm.h:156: error: static declaration of ‘lrintf’ follows non-static declaration
  ./libavutil/libm.h:163: error: static declaration of ‘round’ follows non-static declaration
  ./libavutil/libm.h:170: error: static declaration of ‘roundf’ follows non-static declaration
  ./libavutil/libm.h:177: error: static declaration of ‘trunc’ follows non-static declaration
  ./libavutil/libm.h:184: error: static declaration of ‘truncf’ follows non-static declaration
  make: *** [libavdevice/alldevices.o] Error 1
  </code></pre>