Remove superfluous newlines in function prototypes.

These were introduced by pgindent due to fixe to broken
indentation (c.f. 8255c7a5ee). Previously the mis-indentation of
function prototypes was creatively used to reduce indentation in a few
places.

As that formatting only exists in master and REL_12_STABLE, it seems
better to fix it in both, rather than having some odd indentation in
v12 that somebody might copy for future patches or such.

Author: Andres Freund
Discussion: https://postgr.es/m/20190728013754.jwcbe5nfyt3533vx@alap3.anarazel.de
Backpatch: 12-

src/include/access/gist_private.h

@@ -473,8 +473,7 @@ extern bool gistPageRecyclable(Page page);
 extern void gistfillbuffer(Page page, IndexTuple *itup, int len,
 						   OffsetNumber off);
 extern IndexTuple *gistextractpage(Page page, int *len /* out */ );
-extern IndexTuple *gistjoinvector(
-								  IndexTuple *itvec, int *len,
+extern IndexTuple *gistjoinvector(IndexTuple *itvec, int *len,
 								  IndexTuple *additvec, int addlen);
 extern IndexTupleData *gistfillitupvec(IndexTuple *vec, int veclen, int *memlen);
 

src/include/replication/logical.h

@@ -17,8 +17,7 @@
 
 struct LogicalDecodingContext;
 
-typedef void (*LogicalOutputPluginWriterWrite) (
-												struct LogicalDecodingContext *lr,
+typedef void (*LogicalOutputPluginWriterWrite) (struct LogicalDecodingContext *lr,
 												XLogRecPtr Ptr,
 												TransactionId xid,
 												bool last_write
@@ -26,8 +25,7 @@ typedef void (*LogicalOutputPluginWriterWrite) (
 
 typedef LogicalOutputPluginWriterWrite LogicalOutputPluginWriterPrepareWrite;
 
-typedef void (*LogicalOutputPluginWriterUpdateProgress) (
-														 struct LogicalDecodingContext *lr,
+typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingContext *lr,
 														 XLogRecPtr Ptr,
 														 TransactionId xid
 );
@@ -102,8 +100,7 @@ extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin,
 														 LogicalOutputPluginWriterPrepareWrite prepare_write,
 														 LogicalOutputPluginWriterWrite do_write,
 														 LogicalOutputPluginWriterUpdateProgress update_progress);
-extern LogicalDecodingContext *CreateDecodingContext(
-													 XLogRecPtr start_lsn,
+extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn,
 													 List *output_plugin_options,
 													 bool fast_forward,
 													 XLogPageReadCB read_page,

src/include/replication/reorderbuffer.h

@@ -292,34 +292,29 @@ typedef struct ReorderBufferTXN
 typedef struct ReorderBuffer ReorderBuffer;
 
 /* change callback signature */
-typedef void (*ReorderBufferApplyChangeCB) (
-											ReorderBuffer *rb,
+typedef void (*ReorderBufferApplyChangeCB) (ReorderBuffer *rb,
 											ReorderBufferTXN *txn,
 											Relation relation,
 											ReorderBufferChange *change);
 
 /* truncate callback signature */
-typedef void (*ReorderBufferApplyTruncateCB) (
-											  ReorderBuffer *rb,
+typedef void (*ReorderBufferApplyTruncateCB) (ReorderBuffer *rb,
 											  ReorderBufferTXN *txn,
 											  int nrelations,
 											  Relation relations[],
 											  ReorderBufferChange *change);
 
 /* begin callback signature */
-typedef void (*ReorderBufferBeginCB) (
-									  ReorderBuffer *rb,
+typedef void (*ReorderBufferBeginCB) (ReorderBuffer *rb,
 									  ReorderBufferTXN *txn);
 
 /* commit callback signature */
-typedef void (*ReorderBufferCommitCB) (
-									   ReorderBuffer *rb,
+typedef void (*ReorderBufferCommitCB) (ReorderBuffer *rb,
 									   ReorderBufferTXN *txn,
 									   XLogRecPtr commit_lsn);
 
 /* message callback signature */
-typedef void (*ReorderBufferMessageCB) (
-										ReorderBuffer *rb,
+typedef void (*ReorderBufferMessageCB) (ReorderBuffer *rb,
 										ReorderBufferTXN *txn,
 										XLogRecPtr message_lsn,
 										bool transactional,

src/include/storage/sinval.h

@@ -129,8 +129,7 @@ extern volatile sig_atomic_t catchupInterruptPending;
 
 extern void SendSharedInvalidMessages(const SharedInvalidationMessage *msgs,
 									  int n);
-extern void ReceiveSharedInvalidMessages(
-										 void (*invalFunction) (SharedInvalidationMessage *msg),
+extern void ReceiveSharedInvalidMessages(void (*invalFunction) (SharedInvalidationMessage *msg),
 										 void (*resetFunction) (void));
 
 /* signal handler for catchup events (PROCSIG_CATCHUP_INTERRUPT) */

src/include/utils/guc.h

@@ -283,8 +283,7 @@ extern bool trace_sort;
 extern void SetConfigOption(const char *name, const char *value,
 							GucContext context, GucSource source);
 
-extern void DefineCustomBoolVariable(
-									 const char *name,
+extern void DefineCustomBoolVariable(const char *name,
 									 const char *short_desc,
 									 const char *long_desc,
 									 bool *valueAddr,
@@ -295,8 +294,7 @@ extern void DefineCustomBoolVariable(
 									 GucBoolAssignHook assign_hook,
 									 GucShowHook show_hook);
 
-extern void DefineCustomIntVariable(
-									const char *name,
+extern void DefineCustomIntVariable(const char *name,
 									const char *short_desc,
 									const char *long_desc,
 									int *valueAddr,
@@ -309,8 +307,7 @@ extern void DefineCustomIntVariable(
 									GucIntAssignHook assign_hook,
 									GucShowHook show_hook);
 
-extern void DefineCustomRealVariable(
-									 const char *name,
+extern void DefineCustomRealVariable(const char *name,
 									 const char *short_desc,
 									 const char *long_desc,
 									 double *valueAddr,
@@ -323,8 +320,7 @@ extern void DefineCustomRealVariable(
 									 GucRealAssignHook assign_hook,
 									 GucShowHook show_hook);
 
-extern void DefineCustomStringVariable(
-									   const char *name,
+extern void DefineCustomStringVariable(const char *name,
 									   const char *short_desc,
 									   const char *long_desc,
 									   char **valueAddr,
@@ -335,8 +331,7 @@ extern void DefineCustomStringVariable(
 									   GucStringAssignHook assign_hook,
 									   GucShowHook show_hook);
 
-extern void DefineCustomEnumVariable(
-									 const char *name,
+extern void DefineCustomEnumVariable(const char *name,
 									 const char *short_desc,
 									 const char *long_desc,
 									 int *valueAddr,