Deal with the missing dependencies for libuv.

Since libuv.pc is broken at the moment, try to determine libuv's
dependencies ourselves.  This ports most of the checks from libuv into
our CMake build, and fixes the build on other unix platforms.

src/CMakeLists.txt

@@ -1,3 +1,5 @@
+include(CheckLibraryExists)
+
 file( GLOB NEOVIM_SOURCES *.c )
 
 foreach(sfile ${NEOVIM_SOURCES})
@@ -25,25 +27,12 @@ if(CMAKE_C_COMPILER_ID MATCHES "Clang")
   endif()
 endif()
 
-# The libraries we link against for nvim
-set(NVIM_LINK_LIBRARIES
-    m
-    ${LIBUV_LIBRARIES}
-    ${LUAJIT_LIBRARIES}
-    ${CMAKE_THREAD_LIBS_INIT})
-
-# Add any libraries needed for a specific platform
-if(HAVE_CLOCK_GETTIME)
-  # Work around libuv.a not linking in rt.
-  list(APPEND NVIM_LINK_LIBRARIES rt)
-endif(HAVE_CLOCK_GETTIME)
+# Our dependencies come first.
 
 if (LibIntl_FOUND)
   list(APPEND NVIM_LINK_LIBRARIES ${LibIntl_LIBRARY})
 endif()
 
-include(CheckLibraryExists)
-
 check_library_exists(curses tgetent "" HAVE_LIBCURSES)
 if (HAVE_LIBCURSES)
   list(APPEND NVIM_LINK_LIBRARIES curses)
@@ -52,6 +41,13 @@ else()
   list(APPEND NVIM_LINK_LIBRARIES ${CURSES_LIBRARIES})
 endif()
 
+# Put these last on the link line, since multiple things may depend on them.
+list(APPEND NVIM_LINK_LIBRARIES
+    ${LIBUV_LIBRARIES}
+    ${LUAJIT_LIBRARIES}
+    m
+    ${CMAKE_THREAD_LIBS_INIT})
+
 if(NOT DEFINED ENV{SKIP_EXEC})
   add_executable(nvim ${NEOVIM_SOURCES} ${OS_SOURCES})
   target_link_libraries(nvim ${NVIM_LINK_LIBRARIES})