build: introduce shared libreiserfscore.so and export it

In order to use reiserfs functionality in external programs, we need to
make a shared library and includes available.

This converts both libmisc and libreiserfscore into shared libraries, and
links libmisc into libreiserfscore. We also export the includes and
a pkg-config file.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>

tune/Makefile.am

@@ -5,7 +5,7 @@ reiserfstune_SOURCES = tune.c tune.h
 man_MANS = reiserfstune.8
 EXTRA_DIST = $(man_MANS)
 
-LDADD = $(top_builddir)/reiserfscore/libcore.a $(top_builddir)/lib/libmisc.a
+LDADD = $(top_builddir)/reiserfscore/libreiserfscore.la
 
 install-exec-hook:
 	$(LN_S) reiserfstune $(DESTDIR)$(sbindir)/tunefs.reiserfs