clike compilers: fix cross_* functions' include

A standard C library may not exist for cross-compile
environments, thus the existence of <stdio.h> cannot be
guaranteed.

Use <stddef.h> instead, this header contains compiler-specific
defines thus it usually comes from the compiler.

1 files changed, 13 insertions, 0 deletions

diff --git a/docs/markdown/snippets/clike_compilers_implicit_includes.md b/docs/markdown/snippets/clike_compilers_implicit_includes.md
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+## Clarify of implicitly-included headers in C-like compiler checks
+
+Compiler check methods `compiler.compute_int()`, `compiler.alignment()`
+and `compiler.sizeof()` now have their implicitly-included headers
+corrected and documented.
+
+`<stdio.h>` was included unintentionally when cross-compiling, which
+is less than ideal because there is no guarantee that a standard library
+is available for the target platform. Only `<stddef.h>` is included instead.
+
+For projects that depend on the old behavior, the compiler check methods
+have an optional argument `prefix`, which can be used to specify additional
+`#include` directives.