Make statically linking less painfull

[ruediger]

Currently statically linking is a bit of a hack. This is mainly due to the lack of pkg-config support in leptonica and thus it requires manually tracking all the library dependencies of it (which is quite a lot). Tesseract finally has pkg-config support in 3.02.02 (not in Ubuntu 12.10 though).

• pkg-config issue for leptonica: https://code.google.com/p/leptonica/issues/detail?id=72 (Update: Just as I wrote this issue the pkg-config patch in leptonica was accepted for 1.70)

Statically linking on Ubuntu 12.10 (and Debian) is currently not working because no static version of libjbig is provided. See https://bugs.launchpad.net/ubuntu/+source/jbigkit/+bug/1098361 Which is a dependency of their leptonica package.

This issue was also reported by e-mail

Linking CXX executable ../bin/vobsub2srt
/home/ozone/test/build/lib/libtesseract.a(svutil.o): nella funzione
"SVNetwork::SVNetwork(char const*, int)":
svutil.cpp:(.text+0x42d): attenzione: Using 'getaddrinfo' in statically
linked applications requires at runtime the shared libraries from the
glibc version used for linking
/usr/lib64/gcc/x86_64-slackware-linux/4.7.1/../../../../x86_64-slackware-linux/bin/ld:
/usr/lib64/gcc/x86_64-slackware-linux/4.7.1/../../../../lib64/libstdc++.a(eh_globals.o):
undefined reference to symbol '__tls_get_addr@@GLIBC_2.3'
/usr/lib64/gcc/x86_64-slackware-linux/4.7.1/../../../../x86_64-slackware-linux/bin/ld:
note: '__tls_get_addr@@GLIBC_2.3' is defined in DSO
/lib64/ld-linux-x86-64.so.2 so try adding it to the linker command line
/lib64/ld-linux-x86-64.so.2: could not read symbols: Invalid operation
collect2: error: ld returned 1 exit status