https://bugs.gentoo.org/879657
https://github.com/SWI-Prolog/swipl-devel/commit/2328d9d54c8aa368a4bf0165b1b811d1f31ba0f7
https://github.com/SWI-Prolog/swipl-devel/commit/0d1088443348b71a3624835a19469e2b6cc7e284

From 2328d9d54c8aa368a4bf0165b1b811d1f31ba0f7 Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Tue, 10 Jan 2023 14:08:04 +0100
Subject: [PATCH] cmake: Fix C99 compatibility issues in GCC built-in detection

Future compilers may not support implicit ints or implicit
function declarations, so avoid them, by using an explicit int
type and including <alloca.h> for the alloca function.
--- a/cmake/GCCBuiltins.cmake
+++ b/cmake/GCCBuiltins.cmake
@@ -22,7 +22,7 @@ check_c_source_compiles(
     "volatile int i=0; int main() { return 0; }"
     HAVE_VOLATILE)
 check_c_source_compiles(
-    "static inline foo() { return 0; } int main() { return foo(); }"
+    "static inline int foo() { return 0; } int main() { return foo(); }"
     HAVE_INLINE)
 check_c_source_compiles(
     "int main() { void *p = &&lbl; goto *p; lbl: return 0; }"
@@ -45,7 +45,7 @@ check_visibility()
 # Builtin functions that lead to conflicts
 
 check_c_source_compiles(
-    "int main() { char *s = alloca(10); return s!=0; }"
+    "#include <alloca.h>\nint main() { char *s = alloca(10); return s!=0; }"
     HAVE_ALLOCA)
 check_c_source_compiles(
     "#include <math.h>\nint main() { double x; return signbit(x); }"

From 0d1088443348b71a3624835a19469e2b6cc7e284 Mon Sep 17 00:00:00 2001
From: Jan Wielemaker <J.Wielemaker@vu.nl>
Date: Wed, 11 Jan 2023 13:30:34 +0100
Subject: [PATCH] Cleanup some no longer used GCC __builtin checks.

--- a/cmake/GCCBuiltins.cmake
+++ b/cmake/GCCBuiltins.cmake
@@ -9,12 +9,6 @@ check_c_source_compiles(
 check_c_source_compiles(
     "int i=0; int main() { return __builtin_expect(i, 0) ? 0 : 1; }"
     HAVE___BUILTIN_EXPECT)
-check_c_source_compiles(
-    "int i=0; struct {int x[10];} st; int main() { return __builtin_choose_expr(1, i, st); }"
-    HAVE___BUILTIN_CHOOSE_EXPR)
-check_c_source_compiles(
-    "int i=0; int main() { return __builtin_types_compatible_p(typeof(i), int); }"
-    HAVE___BUILTIN_TYPES_COMPATIBLE_P)
 check_c_source_compiles(
     "__thread int i=0; int main() { return 0; }"
     HAVE___THREAD)
@@ -48,5 +42,5 @@ check_c_source_compiles(
     "#include <alloca.h>\nint main() { char *s = alloca(10); return s!=0; }"
     HAVE_ALLOCA)
 check_c_source_compiles(
-    "#include <math.h>\nint main() { double x; return signbit(x); }"
+    "#include <math.h>\nint main() { double x = 0.0; return signbit(x); }"
     HAVE_SIGNBIT)