Second try at fixing ecpglib thread-safety problem.

While Windows (allegedly) has _configthreadlocale() pretty far back,
it seems MinGW didn't acquire support for that till more recently.
Fortunately, we can use an autoconf probe on that toolchain,
instead of guessing whether it's there.  (Hm, I wonder whether Cygwin
will need this also.)

Per buildfarm.

Discussion: https://postgr.es/m/20190121193512.tdmcnic2yjxlufaw@alap3.anarazel.de

5 files changed, 12 insertions, 6 deletions

diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index 2c899a15692..82547f321f3 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -757,6 +757,9 @@
 /* Define to 1 if your compiler understands __builtin_unreachable. */
 #undef HAVE__BUILTIN_UNREACHABLE
 
+/* Define to 1 if you have the `_configthreadlocale' function. */
+#undef HAVE__CONFIGTHREADLOCALE
+
 /* Define to 1 if you have __cpuid. */
 #undef HAVE__CPUID
 
diff --git a/src/include/pg_config.h.win32 b/src/include/pg_config.h.win32
index 396443386a2..a3c44f0fd80 100644
--- a/src/include/pg_config.h.win32
+++ b/src/include/pg_config.h.win32
@@ -596,6 +596,9 @@
 /* Define to 1 if your compiler understands __builtin_unreachable. */
 /* #undef HAVE__BUILTIN_UNREACHABLE */
 
+/* Define to 1 if you have the `_configthreadlocale' function. */
+#define HAVE__CONFIGTHREADLOCALE 1
+
 /* Define to 1 if you have __cpuid. */
 #define HAVE__CPUID 1
 
diff --git a/src/interfaces/ecpg/ecpglib/descriptor.c b/src/interfaces/ecpg/ecpglib/descriptor.c
index 71cef151724..aeb33636607 100644
--- a/src/interfaces/ecpg/ecpglib/descriptor.c
+++ b/src/interfaces/ecpg/ecpglib/descriptor.c
@@ -495,7 +495,7 @@ ECPGget_desc(int lineno, const char *desc_name, int index,...)
 		if (stmt.clocale != (locale_t) 0)
 			stmt.oldlocale = uselocale(stmt.clocale);
 #else
-#ifdef WIN32
+#ifdef HAVE__CONFIGTHREADLOCALE
 		stmt.oldthreadlocale = _configthreadlocale(_ENABLE_PER_THREAD_LOCALE);
 #endif
 		stmt.oldlocale = ecpg_strdup(setlocale(LC_NUMERIC, NULL), lineno);
@@ -517,7 +517,7 @@ ECPGget_desc(int lineno, const char *desc_name, int index,...)
 			setlocale(LC_NUMERIC, stmt.oldlocale);
 			ecpg_free(stmt.oldlocale);
 		}
-#ifdef WIN32
+#ifdef HAVE__CONFIGTHREADLOCALE
 		if (stmt.oldthreadlocale != -1)
 			_configthreadlocale(stmt.oldthreadlocale);
 #endif
diff --git a/src/interfaces/ecpg/ecpglib/ecpglib_extern.h b/src/interfaces/ecpg/ecpglib/ecpglib_extern.h
index 41851d59007..ae2dcfc6172 100644
--- a/src/interfaces/ecpg/ecpglib/ecpglib_extern.h
+++ b/src/interfaces/ecpg/ecpglib/ecpglib_extern.h
@@ -69,7 +69,7 @@ struct statement
 	locale_t	oldlocale;
 #else
 	char	   *oldlocale;
-#ifdef WIN32
+#ifdef HAVE__CONFIGTHREADLOCALE
 	int			oldthreadlocale;
 #endif
 #endif
diff --git a/src/interfaces/ecpg/ecpglib/execute.c b/src/interfaces/ecpg/ecpglib/execute.c
index 81aaf10f088..a9f945e6188 100644
--- a/src/interfaces/ecpg/ecpglib/execute.c
+++ b/src/interfaces/ecpg/ecpglib/execute.c
@@ -1778,7 +1778,7 @@ ecpg_do_prologue(int lineno, const int compat, const int force_indicator,
 	 * Make sure we do NOT honor the locale for numeric input/output since the
 	 * database wants the standard decimal point.  If available, use
 	 * uselocale() for this because it's thread-safe.  Windows doesn't have
-	 * that, but it does have _configthreadlocale().
+	 * that, but it usually does have _configthreadlocale().
 	 */
 #ifdef HAVE_USELOCALE
 	stmt->clocale = newlocale(LC_NUMERIC_MASK, "C", (locale_t) 0);
@@ -1794,7 +1794,7 @@ ecpg_do_prologue(int lineno, const int compat, const int force_indicator,
 		return false;
 	}
 #else
-#ifdef WIN32
+#ifdef HAVE__CONFIGTHREADLOCALE
 	stmt->oldthreadlocale = _configthreadlocale(_ENABLE_PER_THREAD_LOCALE);
 	if (stmt->oldthreadlocale == -1)
 	{
@@ -2019,7 +2019,7 @@ ecpg_do_epilogue(struct statement *stmt)
 	if (stmt->oldlocale)
 	{
 		setlocale(LC_NUMERIC, stmt->oldlocale);
-#ifdef WIN32
+#ifdef HAVE__CONFIGTHREADLOCALE
 		_configthreadlocale(stmt->oldthreadlocale);
 #endif
 	}