Add macros wrapping all usage of gcc's __attribute__.

Until now __attribute__() was defined to be empty for all compilers but
gcc. That's problematic because it prevents using it in other compilers;
which is necessary e.g. for atomics portability.  It's also just
generally dubious to do so in a header as widely included as c.h.

Instead add pg_attribute_format_arg, pg_attribute_printf,
pg_attribute_noreturn macros which are implemented in the compilers that
understand them. Also add pg_attribute_noreturn and pg_attribute_packed,
but don't provide fallbacks, since they can affect functionality.

This means that external code that, possibly unwittingly, relied on
__attribute__ defined to be empty on !gcc compilers may now run into
warnings or errors on those compilers. But there shouldn't be many
occurances of that and it's hard to work around...

Discussion: 54B58BA3.8040302@ohmu.fi
Author: Oskari Saarenmaa, with some minor changes by me.

8 files changed, 13 insertions, 13 deletions

diff --git a/src/bin/pg_ctl/pg_ctl.c b/src/bin/pg_ctl/pg_ctl.c
index 789fe8f25a1..052caffe8db 100644
--- a/src/bin/pg_ctl/pg_ctl.c
+++ b/src/bin/pg_ctl/pg_ctl.c
@@ -120,7 +120,7 @@ static void
 write_stderr(const char *fmt,...)
 /* This extension allows gcc to check the format string for consistency with
    the supplied arguments. */
-__attribute__((format(PG_PRINTF_ATTRIBUTE, 1, 2)));
+pg_attribute_printf(1, 2);
 static void do_advice(void);
 static void do_help(void);
 static void set_mode(char *modeopt);
diff --git a/src/bin/pg_dump/parallel.c b/src/bin/pg_dump/parallel.c
index 1bf76114c09..f58f96b0636 100644
--- a/src/bin/pg_dump/parallel.c
+++ b/src/bin/pg_dump/parallel.c
@@ -81,7 +81,7 @@ static ParallelSlot *GetMyPSlot(ParallelState *pstate);
 static void
 parallel_msg_master(ParallelSlot *slot, const char *modulename,
 					const char *fmt, va_list ap)
-__attribute__((format(PG_PRINTF_ATTRIBUTE, 3, 0)));
+pg_attribute_printf(3, 0);
 static void archive_close_connection(int code, void *arg);
 static void ShutdownWorkersHard(ParallelState *pstate);
 static void WaitForTerminatingWorkers(ParallelState *pstate);
diff --git a/src/bin/pg_dump/pg_backup.h b/src/bin/pg_dump/pg_backup.h
index a936ff81b9d..d484236c4fe 100644
--- a/src/bin/pg_dump/pg_backup.h
+++ b/src/bin/pg_dump/pg_backup.h
@@ -280,7 +280,7 @@ extern void archputs(const char *s, Archive *AH);
 extern int
 archprintf(Archive *AH, const char *fmt,...)
 /* This extension allows gcc to check the format string */
-__attribute__((format(PG_PRINTF_ATTRIBUTE, 2, 3)));
+pg_attribute_printf(2, 3);
 
 #define appendStringLiteralAH(buf,str,AH) \
 	appendStringLiteral(buf, str, (AH)->encoding, (AH)->std_strings)
diff --git a/src/bin/pg_dump/pg_backup_archiver.h b/src/bin/pg_dump/pg_backup_archiver.h
index 144027ce974..620ada53f13 100644
--- a/src/bin/pg_dump/pg_backup_archiver.h
+++ b/src/bin/pg_dump/pg_backup_archiver.h
@@ -378,7 +378,7 @@ struct _tocEntry
 extern int	parallel_restore(struct ParallelArgs *args);
 extern void on_exit_close_archive(Archive *AHX);
 
-extern void warn_or_exit_horribly(ArchiveHandle *AH, const char *modulename, const char *fmt,...) __attribute__((format(PG_PRINTF_ATTRIBUTE, 3, 4)));
+extern void warn_or_exit_horribly(ArchiveHandle *AH, const char *modulename, const char *fmt,...) pg_attribute_printf(3, 4);
 
 extern void WriteTOC(ArchiveHandle *AH);
 extern void ReadTOC(ArchiveHandle *AH);
@@ -429,8 +429,8 @@ extern int	ReconnectToServer(ArchiveHandle *AH, const char *dbname, const char *
 extern void DropBlobIfExists(ArchiveHandle *AH, Oid oid);
 
 void		ahwrite(const void *ptr, size_t size, size_t nmemb, ArchiveHandle *AH);
-int			ahprintf(ArchiveHandle *AH, const char *fmt,...) __attribute__((format(PG_PRINTF_ATTRIBUTE, 2, 3)));
+int			ahprintf(ArchiveHandle *AH, const char *fmt,...) pg_attribute_printf(2, 3);
 
-void		ahlog(ArchiveHandle *AH, int level, const char *fmt,...) __attribute__((format(PG_PRINTF_ATTRIBUTE, 3, 4)));
+void		ahlog(ArchiveHandle *AH, int level, const char *fmt,...) pg_attribute_printf(3, 4);
 
 #endif
diff --git a/src/bin/pg_dump/pg_backup_tar.c b/src/bin/pg_dump/pg_backup_tar.c
index f48d3696b39..309b4b53dbc 100644
--- a/src/bin/pg_dump/pg_backup_tar.c
+++ b/src/bin/pg_dump/pg_backup_tar.c
@@ -115,7 +115,7 @@ static void tarClose(ArchiveHandle *AH, TAR_MEMBER *TH);
 #ifdef __NOT_USED__
 static char *tarGets(char *buf, size_t len, TAR_MEMBER *th);
 #endif
-static int	tarPrintf(ArchiveHandle *AH, TAR_MEMBER *th, const char *fmt,...) __attribute__((format(PG_PRINTF_ATTRIBUTE, 3, 4)));
+static int	tarPrintf(ArchiveHandle *AH, TAR_MEMBER *th, const char *fmt,...) pg_attribute_printf(3, 4);
 
 static void _tarAddFile(ArchiveHandle *AH, TAR_MEMBER *th);
 static TAR_MEMBER *_tarPositionTo(ArchiveHandle *AH, const char *filename);
diff --git a/src/bin/pg_dump/pg_backup_utils.h b/src/bin/pg_dump/pg_backup_utils.h
index 1bcc1a784fa..2e9a69a615d 100644
--- a/src/bin/pg_dump/pg_backup_utils.h
+++ b/src/bin/pg_dump/pg_backup_utils.h
@@ -30,15 +30,15 @@ extern const char *progname;
 extern void set_dump_section(const char *arg, int *dumpSections);
 extern void
 write_msg(const char *modulename, const char *fmt,...)
-__attribute__((format(PG_PRINTF_ATTRIBUTE, 2, 3)));
+pg_attribute_printf(2, 3);
 extern void
 vwrite_msg(const char *modulename, const char *fmt, va_list ap)
-__attribute__((format(PG_PRINTF_ATTRIBUTE, 2, 0)));
+pg_attribute_printf(2, 0);
 extern void on_exit_nicely(on_exit_nicely_callback function, void *arg);
-extern void exit_nicely(int code) __attribute__((noreturn));
+extern void exit_nicely(int code) pg_attribute_noreturn;
 
 extern void
 exit_horribly(const char *modulename, const char *fmt,...)
-__attribute__((format(PG_PRINTF_ATTRIBUTE, 2, 3), noreturn));
+pg_attribute_printf(2, 3) pg_attribute_noreturn;
 
 #endif   /* PG_BACKUP_UTILS_H */
diff --git a/src/bin/psql/common.h b/src/bin/psql/common.h
index eb14d1cd465..54266c1cb14 100644
--- a/src/bin/psql/common.h
+++ b/src/bin/psql/common.h
@@ -21,7 +21,7 @@ extern bool setQFout(const char *fname);
 extern void
 psql_error(const char *fmt,...)
 /* This lets gcc check the format string for consistency. */
-__attribute__((format(PG_PRINTF_ATTRIBUTE, 1, 2)));
+pg_attribute_printf(1, 2);
 
 extern void NoticeProcessor(void *arg, const char *message);
 
diff --git a/src/bin/psql/large_obj.c b/src/bin/psql/large_obj.c
index 709869e88ab..48d2d77a5e8 100644
--- a/src/bin/psql/large_obj.c
+++ b/src/bin/psql/large_obj.c
@@ -14,7 +14,7 @@
 
 static void
 print_lo_result(const char *fmt,...)
-__attribute__((format(PG_PRINTF_ATTRIBUTE, 1, 2)));
+pg_attribute_printf(1, 2);
 
 static void
 print_lo_result(const char *fmt,...)