ext/mysql/libmysql/my_tempnam.lo(.text+0x4c): In function `my_tempnam':
/php-4.3.1/ext/mysql/libmysql/my_tempnam.c:103: the use of `tempnam' is
dangerous, better use `mkstemp'
ext/mysql/libmysql/my_lib.lo(.text+0x3d1): In function `my_dir':
/php-4.3.1/ext/mysql/libmysql/my_lib.c:169: undefined reference to
`errno'
ext/mysql/libmysql/my_lib.lo(.text+0x5ef): In function `my_stat':
/php-4.3.1/ext/mysql/libmysql/my_lib.c:588: undefined reference to
`errno'
ext/mysql/libmysql/my_malloc.lo(.text+0xde): In function `my_malloc':
/php-4.3.1/ext/mysql/libmysql/my_malloc.c:24: undefined reference to
`errno'
ext/mysql/libmysql/my_realloc.lo(.text+0xd5): In function `my_realloc':
/php-4.3.1/ext/mysql/libmysql/my_realloc.c:44: undefined reference to
`errno'
ext/mysql/libmysql/my_delete.lo(.text+0x86): In function `my_delete':
/php-4.3.1/ext/mysql/libmysql/my_delete.c:16: undefined reference to
`errno'
ext/mysql/libmysql/my_tempnam.lo(.text+0x89):/php-4.3.1/ext/mysql/libmys
ql/my_tempnam.c:108: more undefined references to `errno' follow
collect2: ld returned 1 exit status
make: *** [sapi/cli/php] Error 1

Then I change the source of ./ext/mysql/libmysql/mysql.h by adding string:
#include <errno.h>
but the result was the same.

The same error present in RedHat9