pgsql: Revert "Replace pg_restrict by standard restrict"

Revert "Replace pg_restrict by standard restrict"

This reverts commit f0f2c0c1aef95757c4e7f144d5577e2b0d814279.

The original problem that led to the use of pg_restrict was that MSVC
couldn't handle plain restrict, and defining it to something else
would conflict with its __declspec(restrict) that is used in system
header files. In C11 mode, this is no longer a problem, as MSVC
handles plain restrict. This led to the commit to replace pg_restrict
with restrict. But this did not take C++ into account. Standard C++
does not have restrict, so we defined it as something else (for
example, MSVC supports __restrict). But this then again conflicts
with __declspec(restrict) in system header files. So we have to
revert this attempt. The comments are updated to clarify that the
reason for this is now C++ only.

Reported-by: Jelte Fennema-Nio <postgres(at)jeltef(dot)nl>
Reviewed-by: Andres Freund <andres(at)anarazel(dot)de>
Discussion: https://www.postgresql.org/message-id/CAGECzQRoD7chJP1-dneSrhxUJv%2BBRcigoGOO4UwGzaShLot2Yw%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/fa16e7fd84886643f480c36614fa11d45fc6d26f

Modified Files
--------------
configure | 18 ++++++++++++++----
configure.ac | 16 ++++++++++++----
meson.build | 13 +++++++------
src/bin/pg_verifybackup/pg_verifybackup.c | 4 ++--
src/bin/pg_verifybackup/pg_verifybackup.h | 4 ++--
src/common/logging.c | 4 ++--
src/common/string.c | 2 +-
src/include/c.h | 6 ------
src/include/common/logging.h | 4 ++--
src/include/common/string.h | 2 +-
src/include/libpq/pqformat.h | 12 ++++++------
src/include/pg_config.h.in | 4 ++++
12 files changed, 53 insertions(+), 36 deletions(-)