Adopt libtool rules for soname versioning for libflash

Signed-off-by: Stewart Smith <[email protected]>

external/shared/rules.mk

@@ -1 +1,18 @@
-SHARED_NAME=libflash.so.$(shell ../../make_version.sh)
+# NOTE: shared lib versioning has *NOTHING* to do with software package version
+#
+# If source code has changed, revision++
+# if any interfaces have been added, removed, or changed, current++, revision=0
+# if any interfaces have been added, age++
+# if any interfaces have been removed or changed, age=0
+#
+# i.e. AGE refers to backwards compatibility.
+# e.g. If we start with 5.3.0 and we're releasing new version:
+#      - bug fix no api change: 5.4.0
+#      - new API call, backwards compatible otherwise: 6.0.1
+#      - API removed, or changed (i.e. not backwards compat): 6.0.0
+
+LIBFLASH_VERSION_CURRENT=5
+LIBFLASH_VERSION_REVISION=3
+LIBFLASH_VERSION_AGE=0
+
+SHARED_NAME=libflash.so.${LIBFLASH_VERSION_CURRENT}.${LIBFLASH_VERSION_REVISION}.${LIBFLASH_VERSION_AGE}