fix autoconf/automake warnings

Makefile.am

@@ -1,7 +1,7 @@
 AUTOMAKE_OPTIONS = foreign dist-bzip2 1.6
 ACLOCAL_AMFLAGS = -I m4
 
-INCLUDES = $(all_includes) -I$(top_srcdir)/include
+AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include
 SUBDIRS = src include
 
 pkgconfigdir = $(libdir)/pkgconfig

configure.ac

@@ -21,7 +21,7 @@ PKG_CHECK_MODULES(LIBOSMOCORE, libosmocore >= 0.1.13)
 saved_CFLAGS="$CFLAGS"
 CFLAGS="$CFLAGS -fvisibility=hidden "
 AC_MSG_CHECKING([if ${CC} supports -fvisibility=hidden])
-AC_COMPILE_IFELSE([char foo;],
+AC_COMPILE_IFELSE([AC_LANG_SOURCE([char foo;])],
       [ AC_MSG_RESULT([yes])
         SYMBOL_VISIBILITY="-fvisibility=hidden"],
         AC_MSG_RESULT([no]))

src/Makefile.am

@@ -3,7 +3,7 @@
 # documentation before making any modification
 LIBVERSION=0:0:0
 
-INCLUDES = $(all_includes) -I$(top_srcdir)/include/asn1c
+AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include/asn1c
 AM_CFLAGS = -fPIC -Wall $(LIBOSMOCORE_CFLAGS)
 
 lib_LTLIBRARIES = libasn1c.la