build: various fixes

- simplify lua interpreter search
- fix incorrect variable name in BuildLua.cmake
- build PUC Lua with -O2
- silence non-mandatory find_package search for libuv
- simplify Find modules
- Prefer using the explicitly set CI_BUILD over relying on the
  environment variable "CI".

cmake/FindLpeg.cmake

@@ -1,11 +1,4 @@
-find_library(LPEG_LIBRARY NAMES lpeg_a lpeg liblpeg_a)
-
-# Ubuntu-specific workaround to find system paths
-function(ubuntu)
-  set(CMAKE_FIND_LIBRARY_PREFIXES "")
-  find_library(LPEG_LIBRARY NAMES lpeg PATH_SUFFIXES lua/5.1)
-endfunction()
-ubuntu()
+find_library(LPEG_LIBRARY NAMES lpeg_a lpeg liblpeg_a lpeg${CMAKE_SHARED_LIBRARY_SUFFIX} PATH_SUFFIXES lua/5.1)
 
 find_package_handle_standard_args(Lpeg DEFAULT_MSG LPEG_LIBRARY)
 mark_as_advanced(LPEG_LIBRARY)

cmake/FindLuajit.cmake

@@ -1,5 +1,5 @@
 find_path(LUAJIT_INCLUDE_DIR luajit.h
-          PATH_SUFFIXES luajit-2.0 luajit-2.1)
+          PATH_SUFFIXES luajit-2.1)
 
 if(MSVC)
   list(APPEND LUAJIT_NAMES lua51)

cmake/FindLuv.cmake

@@ -1,13 +1,5 @@
-find_path(LUV_INCLUDE_DIR luv/luv.h)
-find_library(LUV_LIBRARY NAMES luv_a luv libluv_a)
-
-# Ubuntu-specific workaround to find system paths
-function(ubuntu)
-  set(CMAKE_FIND_LIBRARY_PREFIXES "")
-  find_path(LUV_INCLUDE_DIR luv/luv.h PATH_SUFFIXES lua5.1)
-  find_library(LUV_LIBRARY NAMES luv PATH_SUFFIXES lua/5.1)
-endfunction()
-ubuntu()
+find_path(LUV_INCLUDE_DIR luv/luv.h PATH_SUFFIXES lua5.1)
+find_library(LUV_LIBRARY NAMES luv_a luv libluv_a luv${CMAKE_SHARED_LIBRARY_SUFFIX} PATH_SUFFIXES lua/5.1)
 
 find_package_handle_standard_args(Luv DEFAULT_MSG
   LUV_LIBRARY LUV_INCLUDE_DIR)

cmake/GenerateVersion.cmake

@@ -7,7 +7,6 @@ execute_process(
   OUTPUT_STRIP_TRAILING_WHITESPACE
   ERROR_QUIET
   RESULT_VARIABLE RES)
-
 if(RES)
   message(STATUS "Using NVIM_VERSION: ${NVIM_VERSION}")
   file(WRITE "${OUTPUT}" "")

cmake/WindowsDllCopy.cmake

@@ -23,7 +23,7 @@ foreach(DLL_NAME ${DLLS})
     message(FATAL_ERROR "Unable to find dependency ${DLL_NAME}")
   endif()
 
-  if($ENV{CI} MATCHES "true")
+  if(CI_BUILD)
     message("Copying ${DLL_NAME} to ${DST}")
   endif()
   execute_process(COMMAND ${CMAKE_COMMAND} -E copy ${DLL_PATH} ${DST})