libgsmhr: Make it safe to decode/encode different streams at once

Basically the reference code has a bunch of global state.
With some minimal patchihg (previous commit) we can ensure that all
that state is within .bss

So what we do it to save/restore the bss section between calls of the
reference code so we can process several in // and we don't have to
completely fix all reference to global state in the reference codec.

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
diff --git a/libgsmhr/Makefile.am b/libgsmhr/Makefile.am
index 15166b4..e6d246d 100644
--- a/libgsmhr/Makefile.am
+++ b/libgsmhr/Makefile.am
@@ -19,6 +19,7 @@
 
 lib_LTLIBRARIES = libgsmhr.la
 libgsmhr_la_SOURCES = $(REFSRC_SRC) libgsmhr.c
+libgsmhr_la_LIBADD = -ldl
 
 clean-local:
 	-rm -rf ${REFSRC_PATH}/*.{c,h} ${REFSRC_PATH}/.downloaded