[devhelp] meson: install public libdevhelp headers

[Sébastien Wilmet <swilmet src gnome org>]

commit 61d496c71dde0011994430fa06c2da33ebee7d34
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sun Mar 11 10:23:12 2018 +0100

    meson: install public libdevhelp headers
    
    The directory is intentionally devhelp-3/, not devhelp-3.0/, to have
    only "3" as the API version, consistently.

 devhelp/meson.build |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/devhelp/meson.build b/devhelp/meson.build
index 11cf13c..efef5d9 100644
--- a/devhelp/meson.build
+++ b/devhelp/meson.build
@@ -47,3 +47,6 @@ library('devhelp-@0@'.format(DEVHELP_API_VERSION),
         dependencies : DEVHELP_DEPS,
         include_directories : [CONFIG_H_INCLUDE_DIR, ROOT_INCLUDE_DIR],
         install : true)
+
+install_headers(libdevhelp_public_headers,
+                subdir : 'devhelp-@0@/devhelp'.format(DEVHELP_API_VERSION))