Changes to make compilation with gcc-6.2.0 successful

Orca translator changes reorder include statements so that system and
PostgreSQL headers are grouped at the top.  Including such headers
within a C++ namespace causes compilation to fail with the new GCC.

The gpmonlib change removes inline keyword.  The new compiler is not
happy with inlining a function defined in an external object.

gpAux/gpperfmon/src/gpmon/gpmonlib.h

@@ -81,7 +81,7 @@ extern int gpsmon_fatalx(const char* fline, int e, const char* fmt, ...);
 extern apr_status_t gpmon_ntohpkt(apr_int32_t magic, apr_int16_t version, apr_int16_t pkttype);
 
 /* get the size of the union packet for smon_to_mon packets*/
-inline size_t get_size_by_pkttype_smon_to_mmon(apr_int16_t pkttype);
+extern size_t get_size_by_pkttype_smon_to_mmon(apr_int16_t pkttype);
 
 /* strings */
 extern char* gpmon_trim(char* s);
@@ -286,7 +286,7 @@ double subtractTimeOfDay(struct timeval* begin, struct timeval* end);
 
 
 /* Set header*/
-inline void gp_smon_to_mmon_set_header(gp_smon_to_mmon_packet_t* pkt, apr_int16_t pkttype);
+extern void gp_smon_to_mmon_set_header(gp_smon_to_mmon_packet_t* pkt, apr_int16_t pkttype);
 
 unsigned int gpdb_getnode_number_metrics(PerfmonNodeType type);
 const char* gpdb_getnodename(PerfmonNodeType type);

src/backend/gpopt/translate/CTranslatorRelcacheToDXL.cpp

@@ -26,21 +26,9 @@
 #define ALLOW_pfree
 #define ALLOW_MemoryContextFreeImpl
 #define ALLOW_CharGetDatum
+#define ALLOW_list_head
 
 #include "postgres.h"
-#include "naucrates/md/CMDIdCast.h"
-#include "naucrates/md/CMDIdScCmp.h"
-
-#include "naucrates/dxl/gpdb_types.h"
-
-#include "naucrates/md/CMDCastGPDB.h"
-#include "naucrates/md/CMDScCmpGPDB.h"
-
-#include "gpopt/translate/CTranslatorUtils.h"
-#include "gpopt/translate/CTranslatorRelcacheToDXL.h"
-#include "gpopt/translate/CTranslatorScalarToDXL.h"
-#include "gpopt/mdcache/CMDAccessor.h"
-
 #include "utils/array.h"
 #include "utils/rel.h"
 #include "utils/relcache.h"
@@ -59,6 +47,19 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_statistic.h"
 
+#include "naucrates/md/CMDIdCast.h"
+#include "naucrates/md/CMDIdScCmp.h"
+
+#include "naucrates/dxl/gpdb_types.h"
+
+#include "naucrates/md/CMDCastGPDB.h"
+#include "naucrates/md/CMDScCmpGPDB.h"
+
+#include "gpopt/translate/CTranslatorUtils.h"
+#include "gpopt/translate/CTranslatorRelcacheToDXL.h"
+#include "gpopt/translate/CTranslatorScalarToDXL.h"
+#include "gpopt/mdcache/CMDAccessor.h"
+
 #undef ALLOW_DatumGetPointer
 #undef ALLOW_ntohl
 #undef ALLOW_memset
@@ -72,6 +73,7 @@
 #undef ALLOW_pfree
 #undef ALLOW_MemoryContextAllocImpl
 #undef ALLOW_MemoryContextFreeImpl
+#undef ALLOW_list_head
 
 #include "gpos/base.h"
 #include "gpos/error/CException.h"

src/backend/gpopt/translate/CTranslatorScalarToDXL.cpp

@@ -15,11 +15,6 @@
 
 #define ALLOW_isnan
 #include "postgres.h"
-#include "gpopt/translate/CTranslatorScalarToDXL.h"
-#include "gpopt/translate/CTranslatorQueryToDXL.h"
-#include "gpopt/translate/CTranslatorUtils.h"
-#include "gpopt/translate/CCTEListEntry.h"
-
 #include "nodes/plannodes.h"
 #include "nodes/parsenodes.h"
 #include "nodes/primnodes.h"
@@ -27,6 +22,11 @@
 #include "utils/date.h"
 #include "utils/numeric.h"
 
+#include "gpopt/translate/CTranslatorScalarToDXL.h"
+#include "gpopt/translate/CTranslatorQueryToDXL.h"
+#include "gpopt/translate/CTranslatorUtils.h"
+#include "gpopt/translate/CCTEListEntry.h"
+
 #include "gpos/base.h"
 #include "gpos/common/CAutoP.h"
 #include "gpos/string/CWStringDynamic.h"