build: slience some unwanted clang-tidy warnings

.clang-tidy

@@ -3,6 +3,10 @@ Checks: >
   Enable all warnings by default. This ensures we don't miss new and useful
   warnings when a new version of clang-tidy is dropped.
 
+  To list all available checks:
+
+      clang-tidy --list-checks --checks="*"
+
   IMPORTANT
   clang-tidy doesn't support comments but we can simulate comments by just
   writing text directly here. These are then interpreted as warnings and will
@@ -55,12 +59,14 @@ Checks: >
   -misc-misplaced-const,
   -misc-no-recursion,
   -performance-no-int-to-ptr,
+  -portability-avoid-pragma-once,
   -readability-function-cognitive-complexity,
   -readability-identifier-length,
   -readability-magic-numbers,
   -readability-math-missing-parentheses,
   -readability-redundant-declaration, Conflicts with our header generation scripts,
   -readability-suspicious-call-argument,
+  -readability-use-concise-preprocessor-directives,
 
   Aliases. These are just duplicates of other warnings and should always be ignored,
   -bugprone-narrowing-conversions,

src/nvim/path.c

@@ -55,22 +55,22 @@ FileComparison path_full_compare(char *const s1, char *const s2, const bool chec
                                  const bool expandenv)
   FUNC_ATTR_NONNULL_ALL
 {
-  char exp1[MAXPATHL];
+  char expanded1[MAXPATHL];
   char full1[MAXPATHL];
   char full2[MAXPATHL];
   FileID file_id_1, file_id_2;
 
   if (expandenv) {
-    expand_env(s1, exp1, MAXPATHL);
+    expand_env(s1, expanded1, MAXPATHL);
   } else {
-    xstrlcpy(exp1, s1, MAXPATHL);
+    xstrlcpy(expanded1, s1, MAXPATHL);
   }
-  bool id_ok_1 = os_fileid(exp1, &file_id_1);
+  bool id_ok_1 = os_fileid(expanded1, &file_id_1);
   bool id_ok_2 = os_fileid(s2, &file_id_2);
   if (!id_ok_1 && !id_ok_2) {
     // If os_fileid() doesn't work, may compare the names.
     if (checkname) {
-      vim_FullName(exp1, full1, MAXPATHL, false);
+      vim_FullName(expanded1, full1, MAXPATHL, false);
       vim_FullName(s2, full2, MAXPATHL, false);
       if (path_fnamecmp(full1, full2) == 0) {
         return kEqualFileNames;