Due to 
http://git.ghostscript.com/?p=ghostpdl.git;a=commit;f=psi/ierrors.h;h=640801c0fd5527c7f183549df4fd2da365e427d4

libspectre fails to build with

spectre-gs.c: In function ‘critic_error_code’:
spectre-gs.c:46:9: error: ‘e_Fatal’ undeclared (first use in this function)
    case e_Fatal:
         ^
spectre-gs.c:46:9: note: each undeclared identifier is reported only once for each function it appears in
spectre-gs.c:51:9: error: ‘e_ExecStackUnderflow’ undeclared (first use in this function)
    case e_ExecStackUnderflow:
         ^
spectre-gs.c: In function ‘spectre_gs_process’:
spectre-gs.c:112:20: error: ‘e_NeedInput’ undeclared (first use in this function)
   error = error == e_NeedInput ? 0 : error;
                    ^
Makefile:529: recipe for target 'libspectre_la-spectre-gs.lo' failed
make[2]: *** [libspectre_la-spectre-gs.lo] Error 1