cmake: honor --with-sha1dc

Author: Edward Thomson

ext/rugged/extconf.rb

@@ -12,6 +12,9 @@
 $CFLAGS << " -O3" unless $CFLAGS[/-O\d/]
 $CFLAGS << " -Wall -Wno-comment"
 
+cmake_flags = [ ENV["CMAKE_FLAGS"] ]
+cmake_flags << "-DUSE_SHA1DC=ON" if with_config("sha1dc")
+
 def sys(cmd)
   puts " -- #{cmd}"
   unless ret = xsystem(cmd)
@@ -77,7 +80,7 @@ def sys(cmd)
     Dir.chdir("build") do
       # On Windows, Ruby-DevKit is MSYS-based, so ensure to use MSYS Makefiles.
       generator = "-G \"MSYS Makefiles\"" if Gem.win_platform?
-      sys("cmake .. -DBUILD_CLAR=OFF -DTHREADSAFE=ON -DBUILD_SHARED_LIBS=OFF -DCMAKE_C_FLAGS=-fPIC -DCMAKE_BUILD_TYPE=RelWithDebInfo #{ENV['CMAKE_FLAGS']} #{generator}")
+      sys("cmake .. -DBUILD_CLAR=OFF -DTHREADSAFE=ON -DBUILD_SHARED_LIBS=OFF -DCMAKE_C_FLAGS=-fPIC -DCMAKE_BUILD_TYPE=RelWithDebInfo #{cmake_flags.join(' ')} #{generator}")
       sys(MAKE)
 
       # "normal" libraries (and libgit2 builds) get all these when they build but we're doing it