Checker nvcc: cleanup.

- Mark variable g:syntastic_cuda_arch as deprecated.
- Create temporary files in the base directory of the file being
  checked, rather than the current directory.
- Remove temporary files after use.

plugin/syntastic.vim

@@ -19,7 +19,7 @@ if has('reltime')
     lockvar! g:_SYNTASTIC_START
 endif
 
-let g:_SYNTASTIC_VERSION = '3.7.0-143'
+let g:_SYNTASTIC_VERSION = '3.7.0-144'
 lockvar g:_SYNTASTIC_VERSION
 
 " Sanity checks {{{1

syntax_checkers/cuda/nvcc.vim

@@ -20,14 +20,18 @@ set cpo&vim
 function! SyntaxCheckers_cuda_nvcc_GetLocList() dict
     let arch_flag = syntastic#util#var('cuda_arch')
     if arch_flag !=# ''
-        let arch_flag = ' -arch=' . arch_flag
+        let arch_flag = '-arch=' . arch_flag
+        call syntastic#log#oneTimeWarn('variable g:syntastic_cuda_arch is deprecated, ' .
+            \ 'please add ' . string(arch_flag) . ' to g:syntastic_cuda_nvcc_args instead')
     endif
 
     let build_opts = {}
+    let dummy = ''
     if index(['h', 'hpp', 'cuh'], expand('%:e', 1), 0, 1) >= 0
         if syntastic#util#var('cuda_check_header', 0)
+            let dummy = expand('%:p:h', 1) . syntastic#util#Slash() . '.syntastic_dummy.cu'
             let build_opts = {
-                \ 'exe_before': 'echo > .syntastic_dummy.cu ;',
+                \ 'exe_before': 'echo > ' . syntastic#util#shescape(dummy) . ' ;',
                 \ 'fname_before': '.syntastic_dummy.cu -include' }
         else
             return []
@@ -35,7 +39,7 @@ function! SyntaxCheckers_cuda_nvcc_GetLocList() dict
     endif
 
     call extend(build_opts, {
-        \ 'args_before': '--cuda -O0 -I .' . arch_flag,
+        \ 'args_before': arch_flag . ' --cuda -O0 -I .',
         \ 'args': syntastic#c#ReadConfig(g:syntastic_cuda_config_file),
         \ 'args_after': '-Xcompiler -fsyntax-only',
         \ 'tail_after': syntastic#c#NullOutput() })
@@ -58,7 +62,13 @@ function! SyntaxCheckers_cuda_nvcc_GetLocList() dict
         \ '%DMaking %*\a in %f,'.
         \ '%f|%l| %m'
 
-    return SyntasticMake({ 'makeprg': makeprg, 'errorformat': errorformat })
+    let loclist = SyntasticMake({ 'makeprg': makeprg, 'errorformat': errorformat })
+
+    if dummy !=# ''
+        call delete(dummy)
+    endif
+
+    return loclist
 endfunction
 
 call g:SyntasticRegistry.CreateAndRegisterChecker({