Revert "pdb, libgimp: more #pragma once, and formatting cleanup"

This reverts commit be3597e3c7.

See https://gitlab.gnome.org/GNOME/gimp/-/issues/14668

pdb/enumcode.pl

@@ -58,10 +58,13 @@ print ENUMFILE <<'LGPL';
 
 LGPL
 
+my $guard = "__GIMP_ENUMS_H__";
 print ENUMFILE <<HEADER;
-#pragma once
+#ifndef $guard
+#define $guard
 
 G_BEGIN_DECLS
+
 HEADER
 
 foreach (sort keys %enums) {
@@ -112,7 +115,10 @@ void           gimp_enums_init           (void);
 
 const gchar ** gimp_enums_get_type_names (gint *n_type_names);
 
+
 G_END_DECLS
+
+#endif /* $guard */
 HEADER
 
 close ENUMFILE;

pdb/lib.pl

@@ -840,13 +840,15 @@ SECTION_DOCS
         print PFILE $lgpl_top;
         print PFILE " * gimp_pdb_headers.h\n";
         print PFILE $lgpl_bottom;
+	my $guard = "__GIMP_PDB_HEADERS_H__";
 	print PFILE <<HEADER;
-#pragma once
-
 #if !defined (__GIMP_H_INSIDE__) && !defined (GIMP_COMPILATION)
 #error "Only <libgimp/gimp.h> can be included directly."
 #endif
 
+#ifndef $guard
+#define $guard
+
 HEADER
 	my @groups;
 	foreach $group (keys %out) {
@@ -864,6 +866,7 @@ HEADER
 	}
 	print PFILE <<HEADER;
 
+#endif /* $guard */
 HEADER
 	close PFILE;
 	&write_file($gimp_pdb_headers, $destdir);