As reported by Rainer Jung, Curl may not be mandatory to build
ModSecurity core. This patch make it optional by:
- Concentrate all downloads using curl on msc_remote_rules.c
- Split Curl build definitions checks into: WITH_CURL, WITH_REMOTE_RULES
and WITH_CRYPTO.
- WITH_CURL: Contains Culr headers and binaries during the build time.
- WITH_REMOTE_RULES: Currently enabled if Curl is present.
- WITH_CRYPTO: Set if apr tool was compiled with crypto support.
- Renames msc_remote_grab_content to msc_remote_download_content
Initially those directives were only able to load content from a
local file. This commit extends this functionality allowing the user to
provide an HTTP URI that can be downloaded and loaded by ModSecurity.
Initially the download is associated with a server restart. For next
versions we expect to load such resources as it become outdated (Without
need to resetart the server).
Now searching for yajl using find_yajl.m4 macro file instead
of using pkg-config directly. If YAJL was not found or if it
was disabled in the configure phase, the code will be compiled
without JSON support.