This patch moves the GSM-specific functions to the new library
libosmogsm which is provided by libosmocore.

I have also moved generate_backtrace() to backtrace.c instead
of gsm_utils.c, otherwise the timer and msgfile tests depend on
libosmogsm.

Signed-off-by: Pablo Neira Ayuso <pablo@gnumonks.org>
diff --git a/Makefile.am b/Makefile.am
index 93254e8..e391de8 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -5,7 +5,7 @@
 SUBDIRS = include src tests
 
 pkgconfigdir = $(libdir)/pkgconfig
-pkgconfig_DATA = libosmocore.pc libosmocodec.pc libosmovty.pc
+pkgconfig_DATA = libosmocore.pc libosmocodec.pc libosmovty.pc libosmogsm.pc
 
 BUILT_SOURCES = $(top_srcdir)/.version
 $(top_srcdir)/.version: