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>

mkreiserfs/Makefile.am

@@ -4,7 +4,7 @@ mkreiserfs_SOURCES = mkreiserfs.c
 man_MANS = mkreiserfs.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) mkreiserfs $(DESTDIR)$(sbindir)/mkfs.reiserfs