Created attachment 28966 [details]
Preprocessed source

I'm trying to build spandsp using musl libc and found that sqrt() & pow() compilation is broken when using <tgmath.h> with gcc-4.8, but no errors with gcc-4.2.4.
Preprocessed source are the same using both gcc versions (can be found in the attached file).
According to the one of the musl developers, it can be related to the "tgmath __RETCAST magic" http://www.openwall.com/lists/musl/2012/12/14/6
musl's tgmath.h source can be found at http://git.musl-libc.org/cgit/musl/tree/include/tgmath.h

/bin/sh ../libtool --tag=CC   --mode=compile gcc -DHAVE_CONFIG_H -I. -I..  -I/usr/include/libxml2 -DNDEBUG -msse2 -Wunused-but-set-variable -std=gnu99 -ffast-math -Wall -Wunused-variable -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -fvisibility=hidden -DHAVE_VISIBILITY=1  -pedantic -MT awgn.lo -MD -MP -MF .deps/awgn.Tpo -c -o awgn.lo awgn.c
libtool: compile:  gcc -DHAVE_CONFIG_H -I. -I.. -I/usr/include/libxml2 -DNDEBUG -msse2 -Wunused-but-set-variable -std=gnu99 -ffast-math -Wall -Wunused-variable -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -fvisibility=hidden -DHAVE_VISIBILITY=1 -pedantic -MT awgn.lo -MD -MP -MF .deps/awgn.Tpo -c awgn.c  -fPIC -DPIC -o .libs/awgn.o
awgn.c: In function 'awgn_init_dbov':
awgn.c:109:5: error: void value not ignored as it ought to be
     s->rms = pow(10.0, level/20.0)*32768.0;
     ^
awgn.c: In function 'awgn':
awgn.c:165:9: error: void value not ignored as it ought to be
         fac = sqrt(-2.0*log(r)/r);
         ^
awgn.c:165:9: error: void value not ignored as it ought to be
awgn.c:165:9: error: void value not ignored as it ought to be
awgn.c:165:9: error: void value not ignored as it ought to be



Please tell me if any other info is needed.