src/Makefile: use VERSION variable consistently

src/Makefile defines incorrect 'liburing.so' version, i.e 2.1 as
opposed to 2.2. This commit makes src/Makefile use correct version
defined in liburing.spec. Along the way we refactor the use of common
variables into Makefile.common and include it into both src/Makefile
and Makefile.

Signed-off-by: Bikal Lem <gbikal+git@gmail.com>

Makefile

@@ -1,7 +1,5 @@
-NAME=liburing
-SPECFILE=$(NAME).spec
-VERSION=$(shell awk '/Version:/ { print $$2 }' $(SPECFILE))
-TAG = $(NAME)-$(VERSION)
+include Makefile.common
+
 RPMBUILD=$(shell `which rpmbuild >&/dev/null` && echo "rpmbuild" || echo "rpm")
 
 INSTALL=install

Makefile.common

@@ -0,0 +1,5 @@
+TOP := $(dir $(CURDIR)/$(word $(words $(MAKEFILE_LIST)),$(MAKEFILE_LIST)))
+NAME=liburing
+SPECFILE=$(TOP)/$(NAME).spec
+VERSION=$(shell awk '/Version:/ { print $$2 }' $(SPECFILE))
+TAG = $(NAME)-$(VERSION)

liburing.spec

@@ -1,5 +1,5 @@
 Name: liburing
-Version: 2.1
+Version: 2.2
 Release: 1%{?dist}
 Summary: Linux-native io_uring I/O access library
 License: (GPLv2 with exceptions and LGPLv2+) or MIT

src/Makefile

@@ -1,3 +1,5 @@
+include ../Makefile.common
+
 prefix ?= /usr
 includedir ?= $(prefix)/include
 libdir ?= $(prefix)/lib
@@ -14,10 +16,8 @@ LINK_FLAGS=
 LINK_FLAGS+=$(LDFLAGS)
 ENABLE_SHARED ?= 1
 
-soname=liburing.so.2
-minor=1
-micro=0
-libname=$(soname).$(minor).$(micro)
+soname=liburing.so
+libname=$(soname).$(VERSION)
 all_targets += liburing.a
 
 ifeq ($(ENABLE_SHARED),1)