[Patch] Use internal pthreads reimplementation only when buildingwith MSVC

Hi

The following patch, which we added to build mingw-postgresql on Fedora, 
makes the internal minimal pthreads reimplementation only used when 
building with MSVC, as on MINGW it causes symbol collisions with the 
symbols provided my winpthreads.

Thanks
Sandro


diff -rupN postgresql-11.5/src/interfaces/ecpg/ecpglib/misc.c 
postgresql-11.5-new/src/interfaces/ecpg/ecpglib/misc.c
--- postgresql-11.5/src/interfaces/ecpg/ecpglib/misc.c 2019-08-05 
23:14:59.000000000 +0200
+++ postgresql-11.5-new/src/interfaces/ecpg/ecpglib/misc.c 2020-04-08 
11:20:39.850738296 +0200
@@ -449,7 +449,7 @@ ECPGis_noind_null(enum ECPGttype type, c
      return false;
  }

-#ifdef WIN32
+#ifdef _MSC_VER
  #ifdef ENABLE_THREAD_SAFETY

  void
diff -rupN 
postgresql-11.5/src/interfaces/ecpg/include/ecpg-pthread-win32.h 
postgresql-11.5-new/src/interfaces/ecpg/include/ecpg-pthread-win32.h
--- postgresql-11.5/src/interfaces/ecpg/include/ecpg-pthread-win32.h 
2019-08-05 23:14:59.000000000 +0200
+++ postgresql-11.5-new/src/interfaces/ecpg/include/ecpg-pthread-win32.h 
2020-04-08 11:20:39.851738296 +0200
@@ -7,7 +7,7 @@

  #ifdef ENABLE_THREAD_SAFETY

-#ifndef WIN32
+#ifndef _MSC_VER

  #include <pthread.h>
  #else
diff -rupN postgresql-11.5/src/interfaces/libpq/fe-connect.c 
postgresql-11.5-new/src/interfaces/libpq/fe-connect.c
--- postgresql-11.5/src/interfaces/libpq/fe-connect.c 2019-08-05 
23:14:59.000000000 +0200
+++ postgresql-11.5-new/src/interfaces/libpq/fe-connect.c 2020-04-08 
11:20:39.853738297 +0200
@@ -50,7 +50,7 @@
  #endif

  #ifdef ENABLE_THREAD_SAFETY
-#ifdef WIN32
+#ifdef _MSC_VER
  #include "pthread-win32.h"
  #else
  #include <pthread.h>
diff -rupN postgresql-11.5/src/interfaces/libpq/fe-secure.c 
postgresql-11.5-new/src/interfaces/libpq/fe-secure.c
--- postgresql-11.5/src/interfaces/libpq/fe-secure.c    2019-08-05 
23:14:59.000000000 +0200
+++ postgresql-11.5-new/src/interfaces/libpq/fe-secure.c 2020-04-08 
11:20:39.854738297 +0200
@@ -48,7 +48,7 @@
  #include <sys/stat.h>

  #ifdef ENABLE_THREAD_SAFETY
-#ifdef WIN32
+#ifdef _MSC_VER
  #include "pthread-win32.h"
  #else
  #include <pthread.h>
diff -rupN postgresql-11.5/src/interfaces/libpq/fe-secure-openssl.c 
postgresql-11.5-new/src/interfaces/libpq/fe-secure-openssl.c
--- postgresql-11.5/src/interfaces/libpq/fe-secure-openssl.c 2019-08-05 
23:14:59.000000000 +0200
+++ postgresql-11.5-new/src/interfaces/libpq/fe-secure-openssl.c 
2020-04-08 11:20:39.855738298 +0200
@@ -47,7 +47,7 @@
  #include <sys/stat.h>

  #ifdef ENABLE_THREAD_SAFETY
-#ifdef WIN32
+#ifdef _MSC_VER
  #include "pthread-win32.h"
  #else
  #include <pthread.h>
diff -rupN postgresql-11.5/src/interfaces/libpq/libpq-int.h 
postgresql-11.5-new/src/interfaces/libpq/libpq-int.h
--- postgresql-11.5/src/interfaces/libpq/libpq-int.h    2019-08-05 
23:14:59.000000000 +0200
+++ postgresql-11.5-new/src/interfaces/libpq/libpq-int.h 2020-04-08 
11:20:39.855738298 +0200
@@ -29,7 +29,7 @@
  #endif

  #ifdef ENABLE_THREAD_SAFETY
-#ifdef WIN32
+#ifdef _MSC_VER
  #include "pthread-win32.h"
  #else
  #include <pthread.h>
diff -rupN postgresql-11.5/src/interfaces/libpq/pthread-win32.c 
postgresql-11.5-new/src/interfaces/libpq/pthread-win32.c
--- postgresql-11.5/src/interfaces/libpq/pthread-win32.c 2019-08-05 
23:14:59.000000000 +0200
+++ postgresql-11.5-new/src/interfaces/libpq/pthread-win32.c 2020-04-08 
11:21:51.674766968 +0200
@@ -10,10 +10,13 @@
  *-------------------------------------------------------------------------
  */

+#ifdef _MSC_VER
+
  #include "postgres_fe.h"

  #include "pthread-win32.h"

+
  DWORD
  pthread_self(void)
  {
@@ -58,3 +61,5 @@ pthread_mutex_unlock(pthread_mutex_t *mp
      LeaveCriticalSection(*mp);
      return 0;
  }
+
+#endif // _MSC_VER