[devhelp] meson: do not hardcode API version

[Sébastien Wilmet <swilmet src gnome org>]

commit 59e91d1ace1c409e85234e2b114411296a52d66a
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sun Mar 11 09:54:40 2018 +0100

    meson: do not hardcode API version

 devhelp/meson.build |    2 +-
 meson.build         |    3 +++
 2 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/devhelp/meson.build b/devhelp/meson.build
index 5b383f1..11cf13c 100644
--- a/devhelp/meson.build
+++ b/devhelp/meson.build
@@ -39,7 +39,7 @@ libdevhelp_private_c_files = [
         'dh-util-lib.c'
 ]
 
-library('devhelp-3',
+library('devhelp-@0@'.format(DEVHELP_API_VERSION),
         [libdevhelp_public_headers,
          libdevhelp_public_c_files,
          libdevhelp_private_headers,
diff --git a/meson.build b/meson.build
index ee6ae4e..e2eb1f3 100644
--- a/meson.build
+++ b/meson.build
@@ -7,6 +7,9 @@ project('devhelp', 'c',
         meson_version : '>= 0.43',
         version : '3.28.1')
 
+# API version, used for parallel installability.
+DEVHELP_API_VERSION = '3'
+
 DEVHELP_DEPS = [
         dependency('gio-2.0', version : '>= 2.40'),
         dependency('gtk+-3.0', version : '>= 3.22'),