Add configs for application/x-javascript

By default the configurations from this repository ensure that
`.js` files are served with the `application/javascript` media
type, compressed, and with far future expires headers. However,
not all users¹ use all the configurations provided by this
project, or in some cases, the headers are overwritten from the
level "beneath" Apache (e.g.: from `php`).

Looking at the results from the HTTP Archive² from 01.09.2014:

  +---+--------------------+--------------------------+
  |   | number of requests |        media type        |
  +---+--------------------+--------------------------+
  | 1 |            7406888 | image/jpeg               |
  | 2 |            4547461 | image/png                |
  | 3 |            4003685 | image/gif                |
  | 4 |            3087744 | text/html                |
* | 5 |            2112777 | text/javascript          |
  | 6 |            1798370 | text/css                 |
* | 7 |            1740983 | application/x-javascript |
* | 8 |            1394717 | application/javascript   |
  |   |                ... |                      ... |
  +---+--------------------+--------------------------+

it's clear that the `application/javascript` media type is used
less often than both `text/javascript` and `application/x-javascript`.

Because of the above, the changes from this commit will ensure that
Apache will serve anything labeled with the `application/x-javascript`,
compressed and with far future expires headers (a previous commit³ did
the same for the files labeled as `text/javascript`).

- - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - -

¹ #27
  #41

² https://www.igvita.com/2013/06/20/http-archive-bigquery-web-performance-answers/

  Query used:

    select count(requestid) as number_of_requests,
           mimetype as media_type
    from [httparchive:runs.2014_09_01_requests]
    group by media_type
    order by number_of_requests desc;

³ db69327

Author: alrra

CHANGELOG.md

@@ -1,5 +1,6 @@
 ### HEAD
 
+* Add configs for files marked as `application/x-javascript`.
 * Add configs for bitmap image files (`.bmp`)
   [[77ccf9e](https://github.com/h5bp/server-configs-apache/commit/77ccf9ec101b20c14a05fdfb50c2db47ed490ad4)].
 * Compress vCard files (`.vcard`/`.vcf`).

dist/.htaccess

@@ -714,6 +714,7 @@ AddDefaultCharset utf-8
                                       "application/vnd.geo+json" \
                                       "application/vnd.ms-fontobject" \
                                       "application/x-font-ttf" \
+                                      "application/x-javascript" \
                                       "application/x-web-app-manifest+json" \
                                       "application/xhtml+xml" \
                                       "application/xml" \
@@ -797,6 +798,7 @@ FileETag None
 
   # JavaScript
     ExpiresByType application/javascript                "access plus 1 year"
+    ExpiresByType application/x-javascript              "access plus 1 year"
     ExpiresByType text/javascript                       "access plus 1 year"
 
   # Manifest files
@@ -851,6 +853,7 @@ FileETag None
 #     <FilesMatch "\.combined\.js$">
 #         Options +Includes
 #         AddOutputFilterByType INCLUDES application/javascript \
+#                                        application/x-javascript \
 #                                        text/javascript
 #         SetOutputFilter INCLUDES
 #     </FilesMatch>

src/web_performance/compression.conf

@@ -52,6 +52,7 @@
                                       "application/vnd.geo+json" \
                                       "application/vnd.ms-fontobject" \
                                       "application/x-font-ttf" \
+                                      "application/x-javascript" \
                                       "application/x-web-app-manifest+json" \
                                       "application/xhtml+xml" \
                                       "application/xml" \

src/web_performance/expires_headers.conf

@@ -35,6 +35,7 @@
 
   # JavaScript
     ExpiresByType application/javascript                "access plus 1 year"
+    ExpiresByType application/x-javascript              "access plus 1 year"
     ExpiresByType text/javascript                       "access plus 1 year"
 
   # Manifest files

src/web_performance/file_concatenation.conf

@@ -20,6 +20,7 @@
     <FilesMatch "\.combined\.js$">
         Options +Includes
         AddOutputFilterByType INCLUDES application/javascript \
+                                       application/x-javascript \
                                        text/javascript
         SetOutputFilter INCLUDES
     </FilesMatch>

test/fixtures/.htaccess

@@ -667,6 +667,7 @@ AddDefaultCharset utf-8
                                       "application/vnd.geo+json" \
                                       "application/vnd.ms-fontobject" \
                                       "application/x-font-ttf" \
+                                      "application/x-javascript" \
                                       "application/x-web-app-manifest+json" \
                                       "application/xhtml+xml" \
                                       "application/xml" \
@@ -750,6 +751,7 @@ FileETag None
 
   # JavaScript
     ExpiresByType application/javascript                "access plus 1 year"
+    ExpiresByType application/x-javascript              "access plus 1 year"
     ExpiresByType text/javascript                       "access plus 1 year"
 
   # Manifest files
@@ -804,6 +806,7 @@ FileETag None
     <FilesMatch "\.combined\.js$">
         Options +Includes
         AddOutputFilterByType INCLUDES application/javascript \
+                                       application/x-javascript \
                                        text/javascript
         SetOutputFilter INCLUDES
     </FilesMatch>