[libhttpseverywhere] Update README and improve documentation build

[Daniel Brendle <elbren src gnome org>]

commit 84cb6d85cf502e639cbe7ea2d5ee4f39131a13bf
Author: Nirbheek Chauhan <nirbheek centricular com>
Date:   Sat Mar 25 10:42:29 2017 +0530

    Update README and improve documentation build
    
    The build_by_default: kwarg allows custom targets to be built by default
    even if they're not going to be installed.

 README.md   |   13 ++-----------
 meson.build |    7 ++++---
 2 files changed, 6 insertions(+), 14 deletions(-)
---
diff --git a/README.md b/README.md
index 35a8fda..7f26729 100644
--- a/README.md
+++ b/README.md
@@ -59,21 +59,12 @@ Italics are valid debian package names.
 Clone and build the library as follows:
 
 ```
-$ git clone https://github.com/grindhold/libhttpseverywhere
+$ git clone https://git.gnome.org/browse/libhttpseverywhere
 $ cd libhttpseverywhere
-$ mkdir build
-$ cd build
-$ meson ..
+$ meson build && cd build
 $ ninja
 ```
 
-If you want to build the documentation, you'll currently have
-to explicitly build it due to a bug in meson since 0.35.0:
-
-```
-$ ninja devhelp
-```
-
 If you desire to install the library, execute:
 
 ```
diff --git a/meson.build b/meson.build
index 471ee70..9265f1f 100644
--- a/meson.build
+++ b/meson.build
@@ -73,13 +73,15 @@ custom_target('httpseverywhere-typelib',
                install_dir: get_option('libdir') + '/girepository-1.0')
 
 if get_option('enable_valadoc')
-       valadoc = find_program('valadoc', required=false)
+       valadoc = find_program('valadoc')
        custom_target('apidocs',
                    input: httpseverywhere_lib_source,
                    command: [valadoc, '-o', 'devhelp/httpseverywhere-'+api, '--doclet', 'devhelp', '@INPUT@',
                    '--force', '--pkg', 'gee-0.8', '--pkg', 'json-glib-1.0', '--pkg', 'libxml-2.0', '--pkg', 
'libarchive', '--pkg', 'libsoup-2.4'],
                    output: 'devhelp',
-       )
+                   build_by_default: true)
+  install_subdir(meson.current_build_dir()+'/devhelp/httpseverywhere-'+api+'/httpseverywhere-'+api,
+                 install_dir: get_option('datadir')+'/devhelp/books')
 endif
 
 pkgconfig.generate(libraries : httpseverywhere_lib,
@@ -107,4 +109,3 @@ install_data(httpseverywhere_vapi, install_dir: get_option('datadir') + '/vala/v
 
 install_data('data/rulesets.json', install_dir: get_option('datadir') + '/libhttpseverywhere')
 install_data('httpseverywhere-'+api+'.deps', install_dir: get_option('datadir') + '/vala/vapi')
-install_subdir(meson.current_build_dir()+'/devhelp/httpseverywhere-'+api+'/httpseverywhere-'+api, 
install_dir: get_option('datadir')+'/devhelp/books')