Re: some more include removal from headers

On 2026-Mar-15, Álvaro Herrera wrote:

> Hi,
>
> This is what it would look like as a single commit. It passes
> headerscheck and compiles clean for me. CI run in progress:
> https://cirrus-ci.com/build/4615771982135296

Failed in an interesting fashion in macOS and FreeBSD:

[09:14:52.868] ccache cc -Isrc/backend/postgres_lib.a.p -Isrc/include -I../src/include -I/usr/local/include -I/usr/local/include/libxml2 -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -O0 -g -fno-strict-aliasing -fwrapv -fexcess-precision=standard -Wmissing-prototypes -Wpointer-arith -Werror=vla -Werror=unguarded-availability-new -Wendif-labels -Wmissing-format-attribute -Wcast-function-type -Wformat-security -Wimplicit-fallthrough -Wdeclaration-after-statement -Wmissing-variable-declarations -Wno-unused-command-line-argument -Wno-compound-token-split-by-macro -Wno-format-truncation -Wno-cast-function-type-strict -Og -ggdb -DRELCACHE_FORCE_RELEASE -DENFORCE_REGRESSION_TEST_NAME_RESTRICTIONS -fPIC -pthread -DBUILDING_DLL -MD -MQ src/backend/postgres_lib.a.p/storage_ipc_shmem.c.o -MF src/backend/postgres_lib.a.p/storage_ipc_shmem.c.o.d -o src/backend/postgres_lib.a.p/storage_ipc_shmem.c.o -c ../src/backend/storage/ipc/shmem.c
[09:14:52.869] ../src/backend/storage/ipc/shmem.c:748:17: warning: call to undeclared function 'sysconf'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
[09:14:52.869] 748 | os_page_size = sysconf(_SC_PAGESIZE);
[09:14:52.869] | ^
[09:14:52.869] ../src/backend/storage/ipc/shmem.c:748:25: error: use of undeclared identifier '_SC_PAGESIZE'
[09:14:52.869] 748 | os_page_size = sysconf(_SC_PAGESIZE);
[09:14:52.869] | ^
[09:14:52.869] 1 warning and 1 error generated.

AFAICS this is because shmem.c used to get #include <unistd.h>
indirectly through pg_iovec.h and no longer does. Added that. Next run:
https://cirrus-ci.com/build/5651549315137536

--
Álvaro Herrera PostgreSQL Developer — https://www.EnterpriseDB.com/
"It takes less than 2 seconds to get to 78% complete; that's a good sign.
A few seconds later it's at 90%, but it seems to have stuck there. Did
somebody make percentages logarithmic while I wasn't looking?"
http://smylers.hates-software.com/2005/09/08/1995c749.html