Suppress "has no symbols" linker warnings on macOS.

After a recent macOS update, building Postgres produces warnings
that look like this:

    ranlib: warning: 'libpgport_shlib.a(pg_cpu_x86.c.o)' has no symbols
    ranlib: warning: 'libpgport_shlib.a(pg_popcount_x86.c.o)' has no symbols

To fix, add a dummy symbol to files that may otherwise have none.
Per project policy, this is a candidate for back-patching into
out-of-support branches: it suppresses annoying compiler warnings
but changes no behavior.

Reported-by: Zhang Mingli <zmlpostgres@gmail.com>
Reviewed-by: John Naylor <johncnaylorls@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/229aaaf3-f529-44ed-8e50-00cb6909af21%40Spark
Backpatch-through: 13

diff --git a/src/common/protocol_openssl.c b/src/common/protocol_openssl.c
index 089cbd33cca63facadd4c7dcbc0df55a92b3bc66..b8f5d183e0635720ef4843a2c776ea586c951bf2 100644 (file)
--- a/src/common/protocol_openssl.c
+++ b/src/common/protocol_openssl.c
@@ -114,4 +114,10 @@ SSL_CTX_set_max_proto_version(SSL_CTX *ctx, int version)
        return 1;                                       /* success */
 }
 
-#endif                                                 /* !SSL_CTX_set_min_proto_version */
+#else                                                  /* !SSL_CTX_set_min_proto_version */
+
+/* prevent linker complaints about empty module */
+extern int     protocol_openssl_dummy_variable;
+int                    protocol_openssl_dummy_variable = 0;
+
+#endif                                                 /* SSL_CTX_set_min_proto_version */