Compile error if makefile missing -ltr

[ASLeonard]

Hi I was having issues compiling agc using make -f makefile.release agc (to avoid the python binding), and ran into several errors about a missing reference to a clcok like below

stats.c:(.text+0x11c2): undefined reference to `clock_gettime'
 undefined reference to `clock_gettime'
in function `_mi_clock_now':

Adding -lrt to the CLINK line of the makefile fixed this and I was able to get the program running beautifully. My libc is old (2.17) but my gcc is newer (11.2) which may be the cause of the issue, but in case anyone else runs into this it does fix it.

Best, Alex