emacs-28 5e66166714 1/2: Don't fail flymake-tests if `gcc` actually is Clang

[Robert Pluim]

branch: emacs-28
commit 5e66166714f1a06e0312338c2507ae497a36f73a
Author: Mattias Engdegård <mattiase@acm.org>
Commit: Robert Pluim <rpluim@gmail.com>

    Don't fail flymake-tests if `gcc` actually is Clang
    
    * test/lisp/progmodes/flymake-tests.el (flymake-tests--gcc-is-clang)
    (different-diagnostic-types, included-c-header-files): Skip tests that
    depend on the `gcc` command really being GCC and not Clang.
    
    (cherry picked from commit b2167d98432a78442522b7564e22f47d75a98b6f)
---
 test/lisp/progmodes/flymake-tests.el | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/test/lisp/progmodes/flymake-tests.el 
b/test/lisp/progmodes/flymake-tests.el
index 2eb4004f10..45cabf2efb 100644
--- a/test/lisp/progmodes/flymake-tests.el
+++ b/test/lisp/progmodes/flymake-tests.el
@@ -140,9 +140,15 @@ SEVERITY-PREDICATE is used to setup
             (should (eq 'flymake-error (face-at-point)))))
       (delete-directory tempdir t))))
 
+(defun flymake-tests--gcc-is-clang ()
+  "Whether the `gcc' command actually runs the Clang compiler."
+  (string-match "[Cc]lang version "
+                (shell-command-to-string "gcc --version")))
+
 (ert-deftest different-diagnostic-types ()
   "Test GCC warning via function predicate."
   (skip-unless (and (executable-find "gcc")
+                    (not (flymake-tests--gcc-is-clang))
                     (version<=
                      "5" (string-trim
                           (shell-command-to-string "gcc -dumpversion")))
@@ -166,7 +172,9 @@ SEVERITY-PREDICATE is used to setup
 
 (ert-deftest included-c-header-files ()
   "Test inclusion of .h header files."
-  (skip-unless (and (executable-find "gcc") (executable-find "make")))
+  (skip-unless (and (executable-find "gcc")
+                    (not (flymake-tests--gcc-is-clang))
+                    (executable-find "make")))
   (let ((flymake-wrap-around nil))
     (flymake-tests--with-flymake
         ("some-problems.h")