Since Ghostscript 9.18 the PostScript interpreter errors were amalgamated
with the errors in the graphics library (gserrors.h), see
http://bugs.ghostscript.com/show_bug.cgi?id=696317

Examples:

e_ExecStackUnderflow -> gs_error_ExecStackUnderflow
e_Fatal -> gs_error_Fatal
e_NeedInput -> gs_error_NeedInput

Packages that still use the e_<SomeError>
fail to build with Ghostscript 9.18.

The real solution would be to use the gs_error_<SomeError> form.

As an interim measure one could add something like:

#define e_ExecStackUnderflow gs_error_ExecStackUnderflow
#define e_Fatal gs_error_Fatal
#define e_NeedInput gs_error_NeedInput