add version number to -lfmap provided by pkg-config

This is intended as a short-term fix to some linking issues caused by
the strange soname configuration currently used in this package, namely
that successfully linking other packages to libfmap depends on a symlink
being created by ldconfig, which is currently created more or less on accident.

Future versions will likely revert this change and come with some other
changes to the Makefile.

BUG=none
TEST=See notes below.
Before:
pkg-config-x86-generic --libs-only-l fmap
-lfmap

After:
pkg-config-x86-generic --libs-only-l fmap
-lfmap-0.3

Change-Id: I103e7661d0a1b322e7b477e28f366da2cc499476
diff --git a/Makefile b/Makefile
index 9fc5c59..232ac94 100644
--- a/Makefile
+++ b/Makefile
@@ -147,7 +147,7 @@
 Version: $(VERSION_MAJOR).$(VERSION_MINOR)
 Requires:
 Cflags: -I$(includedir)
-Libs: -L$(libdir) -lfmap
+Libs: -L$(libdir) -lfmap-$(VERSION_MAJOR).$(VERSION_MINOR)
 endef
 export FMAP_PC