cmake: Implement GPG Agent support.

We currently considering that all non-Windows platforms have the stuff for
it. If it failing or not working, the SVN_ENABLE_AUTH_GPG_AGENT option still
could be disabled.

* CMakeLists.txt
  (options): Declare SVN_ENABLE_AUTH_GPG_AGENT as a reversely dependent option
   on the value of the WIN32 variable, in order to make it OFF on Windows
   and 'ON' on Linux and other platforms, since they should have everything
   required for this feature.
  (gpg_agent): Enable SVN_HAVE_GPG_AGENT if SVN_ENABLE_AUTH_GPG_AGENT is ON.
  (configure summary): Write whether GPG Agent is enabled or not.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1921261 13f79535-47bb-0310-9956-ffa450edef68

Author: rinrab

CMakeLists.txt

@@ -91,6 +91,7 @@ option(SVN_ENABLE_FS_BASE "Enable Subversion Filesystem Base Library (NOT IMPLEM
 option(SVN_ENABLE_NLS "Enable gettext functionality" OFF)
 option(SVN_ENABLE_AUTH_KWALLET "Enable KWallet auth library" OFF)
 option(SVN_ENABLE_AUTH_GNOME_KEYRING "Enable GNOME Keyring for auth credentials" OFF)
+cmake_dependent_option(SVN_ENABLE_AUTH_GPG_AGENT "Enable GPG Agent support" OFF "WIN32" ON)
 
 option(SVN_INSTALL_PRIVATE_H "Install private header files." OFF)
 
@@ -147,6 +148,10 @@ if(SVN_ENABLE_AUTH_KWALLET)
   add_compile_definitions("SVN_HAVE_KWALLET")
 endif()
 
+if(SVN_ENABLE_AUTH_GPG_AGENT)
+  add_compile_definitions("SVN_HAVE_GPG_AGENT")
+endif()
+
 if (SVN_DEBUG)
   add_compile_definitions("SVN_DEBUG")
 endif()
@@ -790,6 +795,7 @@ message(STATUS "    Build tools ................... : ${SVN_ENABLE_TOOLS}")
 message(STATUS "    Build test suite .............. : ${SVN_ENABLE_TESTS}")
 message(STATUS "    Enable KWallet integration .... : ${SVN_ENABLE_AUTH_KWALLET}")
 message(STATUS "    Enable Gnome Keyring .......... : ${SVN_ENABLE_AUTH_GNOME_KEYRING}")
+message(STATUS "    Enable GPG Agent support ...... : ${SVN_ENABLE_AUTH_GPG_AGENT}")
 message(STATUS "  Install:")
 message(STATUS "    Install prefix: ............... : ${CMAKE_INSTALL_PREFIX}")
 message(STATUS "    Install private headers: ...... : ${SVN_INSTALL_PRIVATE_H}")