title: ld lookup to find library
body: <p>I'm cross compiling to an arm embedded system and receiving an error that I have questions about. Here is the error:</p>
  
  <pre><code>[ 19%] Built target cxjpeg-6b
  Linking CXX shared library /home/botbear/JAUS++-2.110519-   src/libraries/jaus++/2.0/lib/libcxutils.so
  /home/botbear/openwrt/trunk/staging_dir/toolchain-arm_v6k_gcc-linaro_uClibc-    0.9.32_eabi/lib/gcc/arm-openwrt-linux-uclibcgnueabi/4.5.4/../../../../arm-openwrt-linux-    uclibcgnueabi/bin/ld: cannot find -lpng 
  collect2: ld returned 1 exit status
  make[2]: *** [/home/botbear/JAUS++-2.110519-src/libraries/jaus++/2.0/lib/libcxutils.so]     Error 1
  make[1]: *** [libcxutils/CxUtils/libcxutils/CMakeFiles/cxutils.dir/all] Error 2
  make: *** [all] Error 2
  </code></pre>
  
  <p>As you can see the linker is looking for a static library named 'libpng'.  In addition to the libpng lib., the command in the sub-make file using the -l switch to link to the following libraries: -lpng -lz -lX11 -lXtst -lpthread -Wl.  All of the libraries (libpng,libz,libX11, etc) are in my host /usr/lib/ directory but my target toolchain does not have the the libraries.  My question is if I manually recompile the libraries with my target compiler will that solved my problem? Or I'm going to have find and install packages for each of the libraries for my target platform.</p>
  
  <p>Thanks in advance. </p>