Define EXEC_BACKEND in pg_config_manual.h

It was for unclear reasons defined in a separate location, which makes
it more cumbersome to override for testing, and it also did not have
any prominent documentation.  Move to pg_config_manual.h, where
similar things are already collected.

The previous definition on the command-line had the effect of defining
it to the value 1, but now that we don't need that anymore we just
define it to empty, to simplify manual editing a bit.

Reviewed-by: Tom Lane <[email protected]>
Discussion: https://www.postgresql.org/message-id/flat/b7053ba8-b008-5335-31de-2fe4fe41ef0f%402ndquadrant.com

1 files changed, 13 insertions, 0 deletions

diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h
index d74a8dd8083..b7410ff51e5 100644
--- a/src/include/pg_config_manual.h
+++ b/src/include/pg_config_manual.h
@@ -123,6 +123,19 @@
 #define ALIGNOF_BUFFER	32
 
 /*
+ * If EXEC_BACKEND is defined, the postmaster uses an alternative method for
+ * starting subprocesses: Instead of simply using fork(), as is standard on
+ * Unix platforms, it uses fork()+exec() or something equivalent on Windows,
+ * as well as lots of extra code to bring the required global state to those
+ * new processes.  This must be enabled on Windows (because there is no
+ * fork()).  On other platforms, it's only useful for verifying those
+ * otherwise Windows-specific code paths.
+ */
+#if defined(WIN32) && !defined(__CYGWIN__)
+#define EXEC_BACKEND
+#endif
+
+/*
  * Disable UNIX sockets for certain operating systems.
  */
 #if defined(WIN32)