Hello,
I'm trying to cross-compile the Qpid Proton library, which is an AMQP 1.0 messaging library developed by Apache.
The library is this one: https://qpid.apache.org/proton/
In particular, I'm interested in building the C library only, in order to run, inside OpenWrt, a program which is using this library to send AMQP messages.
In order to build it, however, it relies on cmake, which is not available inside OpenWrt.
So, I'm trying to cross-compile it using the OpenWrt SDK. I already have the toolchain, which I used to successfully compile other smaller project, using only make.
Following the Qpid Proton installation instructions (which I put in a pastebin for your reference: https://pastebin.com/Z1YjVu5m, I'm currently running:
$ mkdir build
$ cd build
$ cmake .. -DCMAKE_CXX_COMPILER=x86_64-openwrt-linux-musl-g++ -DCMAKE_INSTALL_PREFIX=/usr -DSYSINSTALL_BINDINGS=ON -DBUILD_GO=OFF -DBUILD_PYTHON=OFF -DBUILD_RUBY=OFF -DBUILD_EXAMPLES=OFF
Setting the desired compiler for my platform (x86_64-openwrt-linux-musl-g++).
Unfortunately, it always fails with these errors:
/home/fr483/OpenWrt-V2X/staging_dir/toolchain-x86_64_gcc-7.3.0_musl/lib/gcc/x86_64-openwrt-linux-musl/7.3.0/../../../../x86_64-openwrt-linux-musl/bin/ld: warning: libpthread.so.0, needed by ../libqpid-proton-proactor.so.1.5.1, not found (try using -rpath or -rpath-link)
/home/fr483/OpenWrt-V2X/staging_dir/toolchain-x86_64_gcc-7.3.0_musl/lib/gcc/x86_64-openwrt-linux-musl/7.3.0/../../../../x86_64-openwrt-linux-musl/bin/ld: warning: libc.so.6, needed by ../libqpid-proton-proactor.so.1.5.1, not found (try using -rpath or -rpath-link)
/home/fr483/OpenWrt-V2X/staging_dir/toolchain-x86_64_gcc-7.3.0_musl/lib/gcc/x86_64-openwrt-linux-musl/7.3.0/../../../../x86_64-openwrt-linux-musl/bin/ld: warning: libdl.so.2, needed by /usr/lib/x86_64-linux-gnu/libcrypto.so, not found (try using -rpath or -rpath-link)
/usr/lib/x86_64-linux-gnu/libcrypto.so: undefined reference to `setcontext@GLIBC_2.2.5'
../libqpid-proton-proactor.so.1.5.1: undefined reference to `accept@GLIBC_2.2.5'
/usr/lib/x86_64-linux-gnu/libcrypto.so: undefined reference to `__vfprintf_chk@GLIBC_2.3.4'
../libqpid-proton-proactor.so.1.5.1: undefined reference to `send@GLIBC_2.2.5'
../libqpid-proton-proactor.so.1.5.1: undefined reference to `connect@GLIBC_2.2.5'
../libqpid-proton-proactor.so.1.5.1: undefined reference to `__errno_location@GLIBC_2.2.5'
/usr/lib/x86_64-linux-gnu/libsasl2.so: undefined reference to `uname@GLIBC_2.2.5'
/usr/lib/x86_64-linux-gnu/libcrypto.so: undefined reference to `closelog@GLIBC_2.2.5'
..............
The problem seems to be related to the fact that it is not able to fing some required libraries for cross-compilation, such as libpthread.so.0.
As it is the first time in which I trying to use the SDK to compile with cmake, is there a (relatively) easy way to solve this problem? How can I tell cmake to look for libraries inside the OpenWrt SDK? Do I need to cross-compile each single library dependency?
Thank you very much in advance!