freebsd: Fixes for the compilation of libosmocore on FreeBSD

alloca.h is not available on FreeBSD, use the default autoconf
function to check for it, there is a complete list[1] of what to
do for using alloca but let us see how far we get with this test.

Include netinet/in.h for the IPv4 and IPv6 socket address. Check
for dlopen in libraries and use this instead of linking -dl.

[1] http://www.gnu.org/s/hello/manual/autoconf/Particular-Functions.html

configure.ac

@@ -19,6 +19,10 @@ AC_CONFIG_MACRO_DIR([m4])
 dnl checks for header files
 AC_HEADER_STDC
 AC_CHECK_HEADERS(execinfo.h sys/select.h sys/socket.h syslog.h ctype.h)
+# for src/conv.c
+AC_FUNC_ALLOCA
+AC_SEARCH_LIBS([dlopen], [dl dld], [LIBRARY_DL="$LIBS";LIBS=""])
+AC_SUBST(LIBRARY_DL)
 
 AC_PATH_PROG(DOXYGEN,doxygen,false)
 AM_CONDITIONAL(HAVE_DOXYGEN, test $DOXYGEN != false)

src/Makefile.am

@@ -19,7 +19,7 @@ libosmocore_la_SOURCES = timer.c select.c signal.c msgb.c bits.c \
 
 if ENABLE_PLUGIN
 libosmocore_la_SOURCES += plugin.c
-libosmocore_la_LDFLAGS = -version-info $(LIBVERSION) -ldl
+libosmocore_la_LDFLAGS = -version-info $(LIBVERSION) $(LIBRARY_DL)
 else
 libosmocore_la_LDFLAGS = -version-info $(LIBVERSION)
 endif

src/conv.c

@@ -29,8 +29,10 @@
 /*! \file conv.c
  *  \file Osmocom convolutional encoder and decoder
  */
-
+#include "config.h"
+#ifdef HAVE_ALLOCA_H
 #include <alloca.h>
+#endif
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>

src/socket.c

@@ -18,6 +18,8 @@
 #include <sys/socket.h>
 #include <sys/types.h>
 
+#include <netinet/in.h>
+
 #include <stdio.h>
 #include <unistd.h>
 #include <stdint.h>