Re: Make foo=null a warning by default.

> [...] Done.

All looks well, but I just noticed a warning:

  gcc -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels
-Wmissing-format-attribute-Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard
-Wno-format-truncation-O2 -I. -I. -I../../../../src/include  -D_GNU_SOURCE   -c -o guc.o guc.c
 
  guc.c:4090:3: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types]
    &transform_null_equals,
    ^
  guc.c:4090:3: note: (near initialization for ‘ConfigureNamesEnum[16].variable’)

Too bad, gcc does not like an (enum*) there. Maybe cast to (int *), or 
declare the variable as an int (which seems to be what is done for 
others)?

-- 
Fabien.