pgsql: meson: Include CFLAGS/c_args in summary and pg_config output

meson: Include CFLAGS/c_args in summary and pg_config output

Previously arguments passed in via CFLAGS/-Dc_args were neither displayed in
meson's summary, nor in pg_config's output.

Reported-by: "wangw.fnst@fujitsu.com" <wangw.fnst@fujitsu.com>
Discussion: https://postgr.es/m/OS3PR01MB62751847BC9CD2DB7B29AC129E529@OS3PR01MB6275.jpnprd01.prod.outlook.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/1330dcdec0f22fb2b7a621f9a0e6e729e21d50a4

Modified Files
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meson.build             |  4 ++++
src/include/meson.build | 10 +++++++---
2 files changed, 11 insertions(+), 3 deletions(-)