Remove to pre-8.2 coding convention for PG_MODULE_MAGIC

PG_MODULE_MAGIC has been around since 8.2, with 8.1 long since in EOL,
so remove the mention of #ifdef guards for compiling against pre-8.2
sources from the documentation.

Author: Daniel Gustafsson <daniel@yesql.se>

contrib/citext/citext.c

@@ -9,9 +9,7 @@
 #include "utils/formatting.h"
 #include "utils/varlena.h"
 
-#ifdef PG_MODULE_MAGIC
 PG_MODULE_MAGIC;
-#endif
 
 /*
  *		====================

doc/src/sgml/plhandler.sgml

@@ -108,9 +108,7 @@
 #include "catalog/pg_proc.h"
 #include "catalog/pg_type.h"
 
-#ifdef PG_MODULE_MAGIC
 PG_MODULE_MAGIC;
-#endif
 
 PG_FUNCTION_INFO_V1(plsample_call_handler);
 

doc/src/sgml/spi.sgml

@@ -4352,9 +4352,7 @@ INSERT INTO a SELECT * FROM a;
 #include "executor/spi.h"
 #include "utils/builtins.h"
 
-#ifdef PG_MODULE_MAGIC
 PG_MODULE_MAGIC;
-#endif
 
 int64 execq(text *sql, int cnt);
 

doc/src/sgml/xfunc.sgml

@@ -1757,20 +1757,13 @@ CREATE FUNCTION square_root(double precision) RETURNS double precision
     file contains a <quote>magic block</> with the appropriate contents.
     This allows the server to detect obvious incompatibilities, such as code
     compiled for a different major version of
-    <productname>PostgreSQL</productname>.  A magic block is required as of
-    <productname>PostgreSQL</productname> 8.2.  To include a magic block,
+    <productname>PostgreSQL</productname>. To include a magic block,
     write this in one (and only one) of the module source files, after having
     included the header <filename>fmgr.h</>:
 
 <programlisting>
-#ifdef PG_MODULE_MAGIC
 PG_MODULE_MAGIC;
-#endif
 </programlisting>
-
-    The <literal>#ifdef</> test can be omitted if the code doesn't
-    need to compile against pre-8.2 <productname>PostgreSQL</productname>
-    releases.
    </para>
 
    <para>
@@ -2214,9 +2207,7 @@ PG_FUNCTION_INFO_V1(funcname);
 #include "fmgr.h"
 #include "utils/geo_decls.h"
 
-#ifdef PG_MODULE_MAGIC
 PG_MODULE_MAGIC;
-#endif
 
 /* by value */
 
@@ -2554,9 +2545,7 @@ SELECT name, c_overpaid(emp, 1500) AS overpaid
 #include "postgres.h"
 #include "executor/executor.h"  /* for GetAttributeByName() */
 
-#ifdef PG_MODULE_MAGIC
 PG_MODULE_MAGIC;
-#endif
 
 PG_FUNCTION_INFO_V1(c_overpaid);
 

src/test/regress/regress.c

@@ -46,9 +46,7 @@
 extern PATH *poly2path(POLYGON *poly);
 extern void regress_lseg_construct(LSEG *lseg, Point *pt1, Point *pt2);
 
-#ifdef PG_MODULE_MAGIC
 PG_MODULE_MAGIC;
-#endif
 
 
 /*