Port --enable-gcc-warnings to Cygwin, FreeBSD

These platforms have a bug where _Noreturn is empty when 'lint' is
defined.  Problem reported by Ken Brown (Bug#23640).
* configure.ac (GCC_LINT): Rename from 'lint'.
* src/conf_post.h (IF_LINT): Use GCC_LINT, not just 'lint’.

2 files changed, 2 insertions, 3 deletions

diff --git a/configure.ac b/configure.ac
index e88a3a943ac..37a159f4117 100644
--- a/configure.ac
+++ b/configure.ac
@@ -997,7 +997,7 @@ AS_IF([test $gl_gcc_warnings = no],
     gl_WARN_ADD([-Wno-pointer-sign])
   fi
 
-  AC_DEFINE([lint], [1], [Define to 1 if the compiler is checking for lint.])
+  AC_DEFINE([GCC_LINT], [1], [Define to 1 if --enable-gcc-warnings.])
   AC_DEFINE([GNULIB_PORTCHECK], [1], [enable some gnulib portability checks])
   AH_VERBATIM([GNULIB_PORTCHECK_FORTIFY_SOURCE],
   [/* Enable compile-time and run-time bounds-checking, and some warnings,
diff --git a/src/conf_post.h b/src/conf_post.h
index 5d3394fafce..f16f8ee791a 100644
--- a/src/conf_post.h
+++ b/src/conf_post.h
@@ -343,9 +343,8 @@ extern int emacs_setenv_TZ (char const *);
 # define FLEXIBLE_ARRAY_MEMBER
 #endif
 
-/* Use this to suppress gcc's `...may be used before initialized' warnings. */
-#ifdef lint
 /* Use CODE only if lint checking is in effect.  */
+#if defined GCC_LINT || defined lint
 # define IF_LINT(Code) Code
 #else
 # define IF_LINT(Code) /* empty */