Fix underlinking

[ginggs]

libopenlibm should be linked to libm to resolve the symbols logl, exp and powl

[ginggs]

The following warnings in amd64 and i386 builds were fixed by explicitly linking libm:

dpkg-shlibdeps: warning: symbol logl used by debian/libopenlibm1/usr/lib/i386-linux-gnu/libopenlibm.so.1.0 found in none of the libraries
dpkg-shlibdeps: warning: symbol expl used by debian/libopenlibm1/usr/lib/i386-linux-gnu/libopenlibm.so.1.0 found in none of the libraries
dpkg-shlibdeps: warning: symbol powl used by debian/libopenlibm1/usr/lib/i386-linux-gnu/libopenlibm.so.1.0 found in none of the libraries

See: https://buildd.debian.org/status/fetch.php?pkg=openlibm&arch=i386&ver=0.4.1%2bdfsg-1&stamp=1430399652

[ginggs]

I don't know if this is needed for WINNT as well.

[ginggs]

What is worrying is that __fpgetprec is still unresolved on i386:

dpkg-shlibdeps: warning: symbol __fpgetprec used by debian/libopenlibm1/usr/lib/i386-linux-gnu/libopenlibm.so.1.0 found in none of the libraries

According to amd64/bsd_ieeefp.h (included from 387/bsd_ieeefp.h) this is an inline function:
static inline fp_prec_t __fpgetprec(void)

This might have something to do with #55.

[ViralBShah]

I would really prefer not linking to libm, and instead getting those functions compiling in openlibm. Even though more work, it is worth getting it right.

[ginggs]

I've created PR #103 to fix the unresolved symbol __fpgetprec on i386.

[ViralBShah]

So what should we do here for now? Is there risk that libm versions will get called instead of openlibm?

[petercolberg]

For further context, please also see this discussion on the Debian Julia list.

[petercolberg]

I am glad to note that this issue has already been solved in HEAD.

The underlinking issue applies only to version 0.4.1, which does not yet contain definitions of expl, logl, and powl; hence the following error when linking the tests against the shared library:

make[2]: Entering directory '/build/openlibm-0.4.1+dfsg/test'
gcc -D_FORTIFY_SOURCE=2 -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -Wl,-z,relro -g test-double.c 
../libopenlibm.so: undefined reference to `powl'
../libopenlibm.so: undefined reference to `logl'
../libopenlibm.so: undefined reference to `expl'

[ViralBShah]

Can we close this PR?