Hello,

On Emacs master, --enable-checking build fails under macOS.
Patch attached.

$ ./configure \
  CPPFLAGS="-DFD_SETSIZE=65536 -D_DARWIN_UNLIMITED_SELECT -I$(brew --prefix)/include" \
  CFLAGS='-g3 -O0' LDFLAGS="-L$(brew --prefix)/lib" TMPDIR=${HOME}/tmp \
  --enable-checking='yes,glyphs' --enable-check-lisp-object-type \
  --prefix=${HOME}/.local/emacs/$(git branch --show-current) \
  --with-ns --disable-ns-self-contained --without-dbus \
  --with-mailutils --with-native-compilation --with-xwidgets
$ make
...
CC       casefiddle.o
CC       indent.o
CC       search.o
search.c:3428:7: error: call to undeclared library function 'free' with type 'void (void *)'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    free (buffer);
    ^
search.c:3428:7: note: include the header <stdlib.h> or explicitly provide a declaration for 'free'
1 error generated.
make[2]: *** [search.o] Error 1
make[1]: *** [src] Error 2
***
*** "make all" failed with exit status 2.
***
*** You could try to:
*** - run "make bootstrap", which might fix the problem
*** - run "make V=1", which displays the full commands invoked by make,
***   to further investigate the problem
***
make[1]: *** [advice-on-failure] Error 2
make: *** [all] Error 2
$
$ gcc --version
Apple clang version 15.0.0 (clang-1500.3.9.4)
Target: arm64-apple-darwin23.5.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin
$

Best regards,
 Naofumi