HTTP: implement Brotli content encoding

This uses the brotli external library (https://github.com/google/brotli).
Brotli becomes a feature: additional curl_version_info() bit and
structure fields are provided for it and CURLVERSION_NOW bumped.

Tests 314 and 315 check Brotli content unencoding with correct and
erroneous data.

Some tests are updated to accomodate with the now configuration dependent
parameters of the Accept-Encoding header.

1 files changed, 8 insertions, 0 deletions

diff --git a/docs/libcurl/curl_version_info.3 b/docs/libcurl/curl_version_info.3
index 26af1c277..1154f4ce7 100644
--- a/docs/libcurl/curl_version_info.3
+++ b/docs/libcurl/curl_version_info.3
@@ -72,6 +72,12 @@ typedef struct {
 
   const char *libssh_version; /* human readable string */
 
+  /* when 'age' is 4 or higher (7.57.0 or later), the members below also
+     exist  */
+  unsigned int brotli_ver_num; /* Numeric Brotli version
+                                  (MAJOR << 24) | (MINOR << 12) | PATCH */
+  const char *brotli_version; /* human readable string. */
+
 } curl_version_info_data;
 .fi
 
@@ -160,6 +166,8 @@ libcurl was built with support for HTTPS-proxy.
 libcurl was built with multiple SSL backends. For details, see
 \fIcurl_global_sslset(3)\fP.
 (Added in 7.56.0)
+.IP CURL_VERSION_BROTLI
+supports HTTP Brotli content encoding using libbrotlidec (Added in 7.57.0)
 .RE
 \fIssl_version\fP is an ASCII string for the OpenSSL version used. If libcurl
 has no SSL support, this is NULL.