compiling rtmpdump for arm - linux

Question

I am trying to compile rtmpdump (http://rtmpdump.mplayerhq.hu/) for Qnap NAS 419p (arm)
I am not very exprenced with linux or compilation but am trying to learn.
make is complaining that it cant find openssl and im not sure where to start?
[/share/Qdownload/src] # ipkg install openssl
Package openssl (0.9.8v-2) installed in root is up to date.
Nothing to be done
Successfully terminated.
confirms that i have installed openssl
[/share/Qdownload/src] #
[/share/Qdownload/src] # ipkg install zlib
Package zlib (1.2.5-1) installed in root is up to date.
Nothing to be done
Successfully terminated.
[/share/Qdownload/src] #
confirms i have zlib the only other depenance i think i need.
[/share/Qdownload/src] # make linux
make[1]: Entering directory `/share/MD0_DATA/Qdownload/src'
g++ -Wall -O2 -c -o rtmp.o rtmp.cpp
In file included from rtmp.h:44,
from rtmp.cpp:42:
dh.h:22:24: error: openssl/bn.h: No such file or directory
dh.h:23:24: error: openssl/dh.h: No such file or directory
dh.h:25:25: error: openssl/sha.h: No such file or directory
dh.h:26:26: error: openssl/hmac.h: No such file or directory
dh.h:27:25: error: openssl/rc4.h: No such file or directory
In file included from rtmp.h:44,
from rtmp.cpp:42:
dh.h:34: error: 'BIGNUM' was not declared in this scope
dh.h:34: error: 'y' was not declared in this scope
dh.h:34: error: 'BIGNUM' was not declared in this scope
dh.h:34: error: 'p' was not declared in this scope
dh.h:34: error: 'BIGNUM' was not declared in this scope
dh.h:34: error: 'q' was not declared in this scope
dh.h:34: error: initializer expression list treated as compound expression
dh.h:35: error: expected constructor, destructor, or type conversion before '*' token
dh.h:36: error: 'DH' was not declared in this scope
dh.h:36: error: 'dh' was not declared in this scope
dh.h:37: error: 'DH' was not declared in this scope
dh.h:37: error: 'dh' was not declared in this scope
dh.h:37: error: expected primary-expression before '*' token
dh.h:37: error: 'pubkey' was not declared in this scope
dh.h:37: error: expected primary-expression before 'nPubkeyLen'
dh.h:37: error: initializer expression list treated as compound expression
dh.h:38: error: 'DH' was not declared in this scope
dh.h:38: error: 'dh' was not declared in this scope
dh.h:38: error: expected primary-expression before '*' token
dh.h:38: error: 'privkey' was not declared in this scope
dh.h:38: error: expected primary-expression before 'nPrivkeyLen'
dh.h:38: error: initializer expression list treated as compound expression
dh.h:39: error: 'DH' was not declared in this scope
dh.h:39: error: 'dh' was not declared in this scope
dh.h:39: error: expected primary-expression before '*' token
dh.h:39: error: 'pubkey' was not declared in this scope
dh.h:39: error: expected primary-expression before 'nPubkeyLen'
dh.h:39: error: expected primary-expression before '*' token
dh.h:39: error: 'secret' was not declared in this scope
dh.h:39: error: initializer expression list treated as compound expression
dh.h:40: error: variable or field 'DHFree' declared void
dh.h:40: error: 'DH' was not declared in this scope
dh.h:40: error: 'dh' was not declared in this scope
In file included from rtmp.cpp:42:
rtmp.h:97: error: ISO C++ forbids declaration of 'DH' with no type
rtmp.h:97: error: expected ';' before '*' token
rtmp.h:98: error: ISO C++ forbids declaration of 'RC4_KEY' with no type
rtmp.h:98: error: expected ';' before '*' token
rtmp.h:99: error: ISO C++ forbids declaration of 'RC4_KEY' with no type
rtmp.h:99: error: expected ';' before '*' token
rtmp.cpp: In member function 'int RTMP_LIB::CRTMP::ReadN(char*, int)':
rtmp.cpp:653: error: 'struct RTMP_LIB::LNK' has no member named 'rc4keyIn'
rtmp.cpp:654: error: 'struct RTMP_LIB::LNK' has no member named 'rc4keyIn'
rtmp.cpp:654: error: 'RC4' was not declared in this scope
rtmp.cpp: In member function 'bool RTMP_LIB::CRTMP::WriteN(const char*, int)':
rtmp.cpp:672: error: 'struct RTMP_LIB::LNK' has no member named 'rc4keyOut'
rtmp.cpp:674: error: 'struct RTMP_LIB::LNK' has no member named 'rc4keyOut'
rtmp.cpp:674: error: 'RC4' was not declared in this scope
make[1]: *** [rtmp.o] Error 1
make[1]: Leaving directory `/share/MD0_DATA/Qdownload/src'
make: *** [linux] Error 2
[/share/Qdownload/src] #
Thanks for any advice you can give.

Answer 1

Make sure to install the development versions of the openssl and zlib packages.
Also make sure that openssl directory is somewhere in standard system include directories which should be /usr/include and /usr/local/include and some others depending on your tool chain.
But don't take my word for it and execute cpp -v < /dev/null. It runs the GNU C Preprocessor with input from /dev/null. Should print the directory search paths. Look for "#include <...> search starts here:" followed by a list of standard include search paths. This is also the order of inclusion.

Answer 2

If you are compiling for ARM it is not enough to install libraries for your own distro... you need libraries and a cross-compiler which runs on your development machine (probably x86 or x86_64) but generates code for the target platform (ARM).
If you don't have a cross-compiler for this Qnap NAS, this link should help you generate one with crosstool-ng, which is a great tool which helps you build cross-compilers from scratch. Then you will probably need a root filesystem with libraries made for your target platform too.
Everything involving cross-compiling is non-trivial, but we can try to help. What distro are you running on your machine?