Exclude fmgrprotos.h from pgindent processing.

pgindent messes up entries in this file if their names match
typedef names.  While there's reason to avoid choosing conflicting
names, we have some historical exceptions, and there's no guarantee
that more duplicates won't appear in future.  Since this is a derived
file anyway, there's little harm in just excluding it.

I said yesterday that all our derived files are pgindent-clean, or else
explicitly excluded from indentation, but I'd forgotten about this one.
Now that project is really done, as confirmed by a test run.

Discussion: https://postgr.es/m/79ed5348-be7a-b647-dd40-742207186a22@2ndquadrant.com

src/tools/pgindent/README

@@ -101,6 +101,10 @@ the comment block with some dashes:
 
 Odd spacing around typedef names might indicate an incomplete typedefs list.
 
+pgindent will mangle both declaration and definition of a C function whose
+name matches a typedef.  Currently the best workaround is to choose
+non-conflicting names.
+
 pgindent can get confused by #if sequences that look correct to the compiler
 but have mismatched braces/parentheses when considered as a whole.  Usually
 that looks pretty unreadable to humans too, so best practice is to rearrange

src/tools/pgindent/exclude_file_patterns

@@ -10,6 +10,10 @@ src/include/jit/llvmjit\.h$
 # This confuses pgindent, and it's a derived file anyway.
 src/backend/utils/fmgrtab\.c$
 #
+# pgindent might mangle entries in this that match typedef names.
+# Since it's a derived file anyway, just exclude it.
+src/backend/utils/fmgrprotos\.h$
+#
 # kwlist_d files are made by gen_keywordlist.pl.  While we could insist that
 # they match pgindent style, they'd look worse not better, so exclude them.
 kwlist_d\.h$
@@ -35,3 +39,5 @@ src/pl/plperl/Util\.c$
 # Exclude any temporary installations that may be in the tree.
 /tmp_check/
 /tmp_install/
+# ... and for paranoia's sake, don't touch git stuff.
+/\.git/