fortify-headers: Remove __fh_has_builtin()

GCC complains about the `defined` usage here. Just call `__has_builtin` directly.

This fixes the following compile error when compiling strace:
```
In file included from /home/hauke/openwrt/openwrt/staging_dir/toolchain-aarch64_generic_gcc-14.3.0_musl/include/fortify/stdlib.h:27,
                 from number_set.c:14:
/home/hauke/openwrt/openwrt/staging_dir/toolchain-aarch64_generic_gcc-14.3.0_musl/include/fortify/fortify-headers.h:26:30: error: this use of "defined" may not be portable [-Werror=expansion-to-defined]
   26 | #define __fh_has_builtin(x) (__has_builtin(x) || defined(x))
      |                              ^~~~~~~~~~~~~
/home/hauke/openwrt/openwrt/staging_dir/toolchain-aarch64_generic_gcc-14.3.0_musl/include/fortify/fortify-headers.h:28:7: note: in expansion of macro '__fh_has_builtin'
   28 | #if ! __fh_has_builtin(__builtin_trap)
      |       ^~~~~~~~~~~~~~~~
/home/hauke/openwrt/openwrt/staging_dir/toolchain-aarch64_generic_gcc-14.3.0_musl/include/fortify/fortify-headers.h:26:30: error: this use of "defined" may not be portable [-Werror=expansion-to-defined]
   26 | #define __fh_has_builtin(x) (__has_builtin(x) || defined(x))
      |                              ^~~~~~~~~~~~~
/home/hauke/openwrt/openwrt/staging_dir/toolchain-aarch64_generic_gcc-14.3.0_musl/include/fortify/fortify-headers.h:73:29: note: in expansion of macro '__fh_has_builtin'
   73 | #if _FORTIFY_SOURCE  > 2 && __fh_has_builtin (__builtin_dynamic_object_size)
      |                             ^~~~~~~~~~~~~~~~
/home/hauke/openwrt/openwrt/staging_dir/toolchain-aarch64_generic_gcc-14.3.0_musl/include/fortify/fortify-headers.h:26:30: error: this use of "defined" may not be portable [-Werror=expansion-to-defined]
   26 | #define __fh_has_builtin(x) (__has_builtin(x) || defined(x))
      |                              ^~~~~~~~~~~~~
/home/hauke/openwrt/openwrt/staging_dir/toolchain-aarch64_generic_gcc-14.3.0_musl/include/fortify/fortify-headers.h:158:5: note: in expansion of macro '__fh_has_builtin'
  158 | #if __fh_has_builtin (__builtin_mul_overflow_p)
      |     ^~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
```

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

1 files changed, 3 insertions, 11 deletions

diff --git a/include/fortify-headers.h b/include/fortify-headers.h
index f7d8af8..7e84075 100644
--- a/include/fortify-headers.h
+++ b/include/fortify-headers.h
@@ -21,21 +21,13 @@
 #error a compiler with __has_builtin support is required
 #endif
 
-// https://clang.llvm.org/docs/LanguageExtensions.html#has-builtin
-// > __has_builtin should not be used to detect support for a builtin macro; use #ifdef instead.
-#define __fh_has_builtin(x) (__has_builtin(x) || defined(x))
-
-#if ! __fh_has_builtin(__builtin_trap)
-#define __builtin_trap abort
-#endif
-
 #if _FORTIFY_SOURCE > 3
 #warning _FORTIFY_SOURCE > 3 is treated as 3
 #endif
 
 #ifdef __clang__
 
-#if _FORTIFY_SOURCE  > 2 && __fh_has_builtin (__builtin_dynamic_object_size) && __has_attribute(pass_dynamic_object_size)
+#if _FORTIFY_SOURCE  > 2 && __has_builtin (__builtin_dynamic_object_size) && __has_attribute(pass_dynamic_object_size)
 #define _FORTIFY_POSN(n) const __attribute__((pass_dynamic_object_size(n)))
 #else
 #define _FORTIFY_POSN(n) const __attribute__((pass_object_size(n)))
@@ -70,7 +62,7 @@
 #define _FORTIFY_FN(fn) _FORTIFY_FNB(fn); _FORTIFY_INLINE
 
 /* Use __builtin_dynamic_object_size with _FORTIFY_SOURCE>2, if available.  */
-#if _FORTIFY_SOURCE  > 2 && __fh_has_builtin (__builtin_dynamic_object_size)
+#if _FORTIFY_SOURCE  > 2 && __has_builtin (__builtin_dynamic_object_size)
 /* 
  * See:
  * - https://gcc.gnu.org/onlinedocs/gcc/Object-Size-Checking.html
@@ -155,7 +147,7 @@
  * - https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html
  * - https://clang.llvm.org/docs/LanguageExtensions.html#checked-arithmetic-builtins
  */
-#if __fh_has_builtin (__builtin_mul_overflow_p)
+#if __has_builtin (__builtin_mul_overflow_p)
 #define __bmo(x, y) (x != 0 && __builtin_mul_overflow_p(x, y, (__typeof__ ((x) + (y))) 0))
 #else /* !__builtin_mul_overflow_p */
 #define __bmo(x, y) (x != 0 && (x * y) / x != y)